Replaces some borer progression with an upgrade tree (#16704)

* borer wormening

* time to go

* synthetic boring

* lc-chest

* cleans unneeded logic

* warn against only 1 T3+

* _

code/__DEFINES/~skyrat_defines/antagonists.dm

@@ -18,3 +18,25 @@
 
 /// Population requirement for bomb objectives (ninja c4, locate weakpoint, etc.) objectives to appear
 #define BOMB_POP_REQUIREMENT 80
+
+// Borer evolution defines
+// The three primary paths that eventually diverge
+#define BORER_EVOLUTION_SYMBIOTE "Symbiote"
+#define BORER_EVOLUTION_HIVELORD "Hivelord"
+#define BORER_EVOLUTION_DIVEWORM "Diveworm"
+// Just general upgrades that don't take you in a specific direction
+#define BORER_EVOLUTION_GENERAL "General"
+#define BORER_EVOLUTION_START "Start"
+
+// Borer effect flags
+
+/// If the borer is in stealth mode, giving less feedback to hosts at the cost of no health/resource/point gain
+#define BORER_STEALTH_MODE (1<<0)
+/// If the borer is sugar-immune, taking no ill effects from sugar
+#define BORER_SUGAR_IMMUNE (1<<1)
+/// If the borer is able to enter hosts in half the time, if not hiding
+#define BORER_FAST_BORING (1<<2)
+/// If the borer is currently hiding under tables/couches/stairs or appearing on top of them
+#define BORER_HIDING (1<<3)
+/// If the borer can produce eggs without a host
+#define BORER_ALONE_PRODUCTION (1<<4)

code/__HELPERS/~skyrat_helpers/logging.dm

@@ -1,4 +1,4 @@
-//This logs subtler emotes in game.txt, if the conflig flag in config\skyrat\skyrat_config.txt is true.
+/// This logs subtler emotes in game.txt, if the conflig flag in config\skyrat\skyrat_config.txt is true.
 /proc/log_subtler(text)
 	if (CONFIG_GET(flag/log_subtler))
 		WRITE_LOG(GLOB.world_game_log, "SUBTLER EMOTE: [text]")
@@ -6,6 +6,11 @@
 GLOBAL_VAR(character_creation_log)
 GLOBAL_PROTECT(character_creation_log)
 
-//This logs subtler emotes in game.txt, if the conflig flag in config\skyrat\skyrat_config.txt is true.
+/// This logs subtler emotes in game.txt, if the conflig flag in config\skyrat\skyrat_config.txt is true.
 /proc/log_creator(text)
 	WRITE_LOG(GLOB.character_creation_log, "CREATOR LOG: [text]")
+
+/// Logging for borer evolutions
+/proc/log_borer_evolution(text)
+	if (CONFIG_GET(flag/log_uplink))
+		WRITE_LOG(GLOB.world_uplink_log, "BORER EVOLUTION: [text]")

code/modules/antagonists/changeling/powers/panacea.dm

@@ -11,9 +11,12 @@
 /datum/action/changeling/panacea/sting_action(mob/user)
 	to_chat(user, span_notice("We cleanse impurities from our form."))
 	..()
+	// SKYRAT EDIT ADDITION: BORER EGG
 	var/list/bad_organs = list(
 		user.getorgan(/obj/item/organ/internal/body_egg),
-		user.getorgan(/obj/item/organ/internal/zombie_infection))
+		user.getorgan(/obj/item/organ/internal/zombie_infection),
+		user.getorgan(/obj/item/organ/internal/empowered_borer_egg))
+	// SKYRAT EDIT END
 
 	try_to_mutant_cure(user) //SKYRAT EDIT ADDITION
 

modular_skyrat/modules/cortical_borer/code/cortical_borer.dm

@@ -11,10 +11,13 @@ GLOBAL_VAR_INIT(successful_blood_chem, 0)
 GLOBAL_LIST_EMPTY(cortical_borers)
 
 //we need a way of buffing leg speed
-/datum/movespeed_modifier/borer_speed
+/datum/movespeed_modifier/focus_speed
 	multiplicative_slowdown = -0.4
 
-/datum/actionspeed_modifier/borer_speed
+/datum/movespeed_modifier/borer_speed
+	multiplicative_slowdown = -0.5
+
+/datum/actionspeed_modifier/focus_speed
 	multiplicative_slowdown = -0.3
 	id = ACTIONSPEED_ID_BORER
 
@@ -122,24 +125,28 @@ GLOBAL_LIST_EMPTY(cortical_borers)
 	var/chemical_storage = 50
 	///how fast chemicals are gained. Goes up only when inside a host
 	var/chemical_regen = 1
+	/// How much health you gain per level
+	var/health_per_level = 2.5
+	/// How much health regen you gain per level
+	var/health_regen_per_level = 0.02
+	/// How much more chemical storage you gain per level
+	var/chem_storage_per_level = 20
+	/// Chemical regen you gain per level
+	var/chem_regen_per_level = 1
+	/// How many times you've levelled up over all
+	var/level = 0
 	///the list of actions that the borer has
 	var/list/known_abilities = list(/datum/action/cooldown/borer/toggle_hiding,
 									/datum/action/cooldown/borer/choosing_host,
+									/datum/action/cooldown/borer/evolution_tree,
 									/datum/action/cooldown/borer/inject_chemical,
 									/datum/action/cooldown/borer/upgrade_chemical,
 									/datum/action/cooldown/borer/learn_focus,
 									/datum/action/cooldown/borer/upgrade_stat,
-									/datum/action/cooldown/borer/learn_ability,
 									/datum/action/cooldown/borer/force_speak,
 									/datum/action/cooldown/borer/fear_human,
 									/datum/action/cooldown/borer/check_blood,
 	)
-	///the list of actions that the borer could learn
-	var/possible_abilities = list(/datum/action/cooldown/borer/produce_offspring,
-								/datum/action/cooldown/borer/learn_bloodchemical,
-								/datum/action/cooldown/borer/revive_host,
-								/datum/action/cooldown/borer/willing_host,
-	)
 	///the host
 	var/mob/living/carbon/human/human_host
 	//what the host gains or loses with the borer
@@ -183,6 +190,14 @@ GLOBAL_LIST_EMPTY(cortical_borers)
 	var/injection_rate_current = 5
 	/// Cooldown between injecting chemicals
 	COOLDOWN_DECLARE(injection_cooldown)
+	/// Evolutions we've already learned
+	var/list/past_evolutions = list()
+	/// Bitflag of upgrades and effects the borer has
+	var/upgrade_flags = 0
+	/// If the borer has evolved with a genome that locks out others of the same & higher tier
+	var/genome_locked = FALSE
+	/// Multiplier for a borer's negative effects to their host
+	var/host_harm_multiplier = 1
 
 /mob/living/simple_animal/cortical_borer/Initialize(mapload)
 	. = ..()
@@ -205,6 +220,7 @@ GLOBAL_LIST_EMPTY(cortical_borers)
 			mind.add_antag_datum(/datum/antagonist/cortical_borer)
 	for(var/focus_path in subtypesof(/datum/borer_focus))
 		possible_focuses += new focus_path
+	do_evolution(/datum/borer_evolution/base)
 
 /mob/living/simple_animal/cortical_borer/Destroy()
 	human_host = null
@@ -251,8 +267,8 @@ GLOBAL_LIST_EMPTY(cortical_borers)
 		return
 
 	//there needs to be a negative to having a borer
-	if(prob(5) && human_host.getToxLoss() <= 80)
-		human_host.adjustToxLoss(5, TRUE, TRUE)
+	if(prob(5 * host_harm_multiplier * ((upgrade_flags & BORER_STEALTH_MODE) ? 0.1 : 1)) && human_host.getToxLoss() <= (80 * host_harm_multiplier))
+		human_host.adjustToxLoss(5 * host_harm_multiplier, TRUE, TRUE)
 
 	human_host.apply_status_effect(/datum/status_effect/grouped/screwy_hud/fake_healthy, type)
 
@@ -266,43 +282,17 @@ GLOBAL_LIST_EMPTY(cortical_borers)
 
 	//this is regenerating chemical_storage
 	if(chemical_storage < max_chemical_storage)
-		chemical_storage = min(chemical_storage + chemical_regen, max_chemical_storage)
-		if(chemical_storage > max_chemical_storage)
-			chemical_storage = max_chemical_storage
+		if(!(upgrade_flags & BORER_STEALTH_MODE))
+			chemical_storage = min(chemical_storage + chemical_regen, max_chemical_storage)
 
 	//this is regenerating health
 	if(health < maxHealth)
-		health = min(health * health_regen, maxHealth)
-		if(health > maxHealth)
-			health = maxHealth
+		if(!(upgrade_flags & BORER_STEALTH_MODE))
+			health = min(health * health_regen, maxHealth)
 
 	//this is so they can evolve
 	if(timed_maturity < world.time)
-		timed_maturity = world.time + 1 SECONDS
-		maturity_age++
-
-		//20:40, 15:30, 10:20, 5:10
-		var/maturity_threshold = 20
-		if(GLOB.successful_egg_number >= GLOB.objective_egg_borer_number)
-			maturity_threshold -= 2
-		if(length(GLOB.willing_hosts) >= GLOB.objective_willing_hosts)
-			maturity_threshold -= 10
-		if(GLOB.successful_blood_chem >= GLOB.objective_blood_borer)
-			maturity_threshold -= 3
-
-		if(maturity_age == maturity_threshold)
-			if(chemical_evolution < limited_borer) //you can only have a default of 10 at a time
-				chemical_evolution++
-				to_chat(src, span_notice("You gain a chemical evolution point. Spend it to learn a new chemical!"))
-			else
-				to_chat(src, span_warning("You were unable to gain a chemical evolution point due to having the max!"))
-		if(maturity_age >= (maturity_threshold * 2))
-			if(stat_evolution < limited_borer)
-				stat_evolution++
-				to_chat(src, span_notice("You gain a stat evolution point. Spend it to become stronger!"))
-			else
-				to_chat(src, span_warning("You were unable to gain a stat evolution point due to having the max!"))
-			maturity_age = 0
+		mature()
 
 //if it doesnt have a ckey, let ghosts have it
 /mob/living/simple_animal/cortical_borer/attack_ghost(mob/dead/observer/user)
@@ -330,6 +320,8 @@ GLOBAL_LIST_EMPTY(cortical_borers)
 
 //check if the host has sugar
 /mob/living/simple_animal/cortical_borer/proc/host_sugar()
+	if(upgrade_flags & BORER_SUGAR_IMMUNE)
+		return FALSE
 	if(human_host?.reagents?.has_reagent(/datum/reagent/consumable/sugar))
 		return TRUE
 	return FALSE
@@ -387,3 +379,56 @@ GLOBAL_LIST_EMPTY(cortical_borers)
 /mob/living/simple_animal/cortical_borer/start_pulling(atom/movable/AM, state, force, supress_message)
 	to_chat(src, span_warning("You cannot pull things!"))
 	return
+
+/// Called on Life() for the borer to age a bit
+/mob/living/simple_animal/cortical_borer/proc/mature()
+	. = TRUE
+	if(upgrade_flags & BORER_STEALTH_MODE)
+		return FALSE
+	timed_maturity = world.time + 1 SECONDS
+	maturity_age++
+
+	//20:40, 15:30, 10:20, 5:10
+	var/maturity_threshold = 20
+	if(GLOB.successful_egg_number >= GLOB.objective_egg_borer_number)
+		maturity_threshold -= 2
+	if(length(GLOB.willing_hosts) >= GLOB.objective_willing_hosts)
+		maturity_threshold -= 10
+	if(GLOB.successful_blood_chem >= GLOB.objective_blood_borer)
+		maturity_threshold -= 3
+
+	if(maturity_age == maturity_threshold)
+		if(chemical_evolution < limited_borer) //you can only have a default of 10 at a time
+			chemical_evolution++
+			to_chat(src, span_notice("You gain a chemical evolution point. Spend it to learn a new chemical!"))
+		else
+			to_chat(src, span_warning("You were unable to gain a chemical evolution point due to having the max!"))
+	if(maturity_age >= (maturity_threshold * 2))
+		if(stat_evolution < limited_borer)
+			stat_evolution++
+			to_chat(src, span_notice("You gain a stat evolution point. Spend it to become stronger!"))
+		else
+			to_chat(src, span_warning("You were unable to gain a stat evolution point due to having the max!"))
+		maturity_age = 0
+
+/// Use to recalculate a borer's health and chemical stats when something retroactively affects them
+/mob/living/simple_animal/cortical_borer/proc/recalculate_stats()
+	var/old_health = health
+	maxHealth = initial(maxHealth) * (level + 1) * health_per_level
+	health_regen = initial(health_regen) * (level + 1) * health_regen_per_level
+	max_chemical_storage = initial(max_chemical_storage) * (level + 1) * chem_storage_per_level
+	chemical_regen = initial(chemical_regen) * (level + 1) * chem_regen_per_level
+	health = clamp(old_health, 0, maxHealth)
+
+// Only able to spawn from an egg burst from a corpse, starts off stronger
+/mob/living/simple_animal/cortical_borer/empowered
+	maxHealth = 150
+	health = 150
+	health_per_level = 15
+	health_regen_per_level = 0.04
+	stat_evolution = 8
+	chemical_evolution = 8
+	max_chemical_storage = 250
+	chemical_storage = 250
+	chem_regen_per_level = 1.5
+	chem_storage_per_level = 25

modular_skyrat/modules/cortical_borer/code/cortical_borer_abilities.dm

@@ -1,10 +1,11 @@
 #define CHEMICALS_PER_UNIT 2
 #define CHEMICAL_SECOND_DIVISOR 5 SECONDS
+#define OUT_OF_HOST_EGG_COST 50
 
 // Parent of all borer actions
 /datum/action/cooldown/borer
 	icon_icon = 'modular_skyrat/modules/cortical_borer/icons/actions.dmi'
-	cooldown_time = 1 SECONDS
+	cooldown_time = 0
 
 /datum/action/cooldown/borer/Trigger(trigger_flags, atom/target)
 	. = ..()
@@ -41,7 +42,7 @@
 		ui.open()
 
 /datum/action/cooldown/borer/inject_chemical/ui_data(mob/user)
-	var/data = list()
+	var/list/data = list()
 	var/mob/living/simple_animal/cortical_borer/cortical_owner = owner
 	data["amount"] = cortical_owner.injection_rate_current
 	data["energy"] = cortical_owner.chemical_storage / CHEMICALS_PER_UNIT
@@ -81,11 +82,14 @@
 			var/reagent = GLOB.name2reagent[reagent_name]
 			if(!(reagent in cortical_owner.known_chemicals))
 				return
+
 			cortical_owner.reagent_holder.reagents.add_reagent(reagent, cortical_owner.injection_rate_current, added_purity = 1)
 			cortical_owner.reagent_holder.reagents.trans_to(cortical_owner.human_host, cortical_owner.injection_rate_current, methods = INGEST)
+
 			to_chat(cortical_owner.human_host, span_warning("You feel something cool inside of you and a dull ache in your head!"))
 			cortical_owner.chemical_storage -= cortical_owner.injection_rate_current * CHEMICALS_PER_UNIT
 			COOLDOWN_START(cortical_owner, injection_cooldown, (cortical_owner.injection_rate_current / CHEMICAL_SECOND_DIVISOR))
+
 			var/turf/human_turf = get_turf(cortical_owner.human_host)
 			var/logging_text = "[key_name(cortical_owner)] injected [key_name(cortical_owner.human_host)] with [reagent_name] at [loc_name(human_turf)]"
 			cortical_owner.log_message(logging_text, LOG_GAME)
@@ -98,11 +102,103 @@
 /datum/action/cooldown/borer/inject_chemical/ui_status(mob/user, datum/ui_state/state)
 	if(!iscorticalborer(user))
 		return UI_CLOSE
+
 	var/mob/living/simple_animal/cortical_borer/borer = user
+
 	if(!borer.human_host)
 		return UI_CLOSE
 	return ..()
 
+/datum/action/cooldown/borer/evolution_tree
+	name = "Open Evolution Tree"
+	button_icon_state = "newability"
+
+/datum/action/cooldown/borer/evolution_tree/Trigger(trigger_flags)
+	. = ..()
+	if(!.)
+		return FALSE
+	ui_interact(owner)
+
+/datum/action/cooldown/borer/evolution_tree/ui_interact(mob/user, datum/tgui/ui)
+	ui = SStgui.try_update_ui(user, src, ui)
+	if(!ui)
+		ui = new(user, src, "BorerEvolution", name)
+		ui.open()
+
+/datum/action/cooldown/borer/evolution_tree/ui_data(mob/user)
+	var/list/data = list()
+
+	var/static/list/path_to_color = list(
+		BORER_EVOLUTION_DIVEWORM = "red",
+		BORER_EVOLUTION_HIVELORD = "purple",
+		BORER_EVOLUTION_SYMBIOTE = "green",
+		BORER_EVOLUTION_GENERAL = "label",
+	)
+
+	var/mob/living/simple_animal/cortical_borer/cortical_owner = owner
+
+	data["evolution_points"] = cortical_owner.stat_evolution
+
+	for(var/datum/borer_evolution/evolution as anything in cortical_owner.get_possible_evolutions())
+		if(evolution in cortical_owner.past_evolutions)
+			continue
+
+		var/list/evo_data = list()
+
+		evo_data["path"] = evolution
+		evo_data["name"] = initial(evolution.name)
+		evo_data["desc"] = initial(evolution.desc)
+		evo_data["gainFlavor"] = initial(evolution.gain_text)
+		evo_data["cost"] = initial(evolution.evo_cost)
+		evo_data["disabled"] = ((initial(evolution.evo_cost) > cortical_owner.stat_evolution) || (initial(evolution.mutually_exclusive) && cortical_owner.genome_locked))
+		evo_data["evoPath"] = initial(evolution.evo_type)
+		evo_data["color"] = path_to_color[initial(evolution.evo_type)] || "grey"
+		evo_data["tier"] = initial(evolution.tier)
+		evo_data["exclusive"] = initial(evolution.mutually_exclusive)
+
+		data["learnableEvolution"] += list(evo_data)
+
+	for(var/path in cortical_owner.past_evolutions)
+		var/list/evo_data = list()
+		var/datum/borer_evolution/found_evolution = cortical_owner.past_evolutions[path]
+
+		evo_data["name"] = found_evolution.name
+		evo_data["desc"] = found_evolution.desc
+		evo_data["gainFlavor"] = found_evolution.gain_text
+		evo_data["cost"] = found_evolution.evo_cost
+		evo_data["evoPath"] = found_evolution.evo_type
+		evo_data["color"] = path_to_color[found_evolution.evo_type] || "grey"
+		evo_data["tier"] = found_evolution.tier
+
+		data["learnedEvolution"] += list(evo_data)
+	return data
+
+/datum/action/cooldown/borer/evolution_tree/ui_act(action, params)
+	. = ..()
+	if(.)
+		return
+	var/mob/living/simple_animal/cortical_borer/cortical_owner = owner
+	switch(action)
+		if("evolve")
+			var/datum/borer_evolution/to_evolve_path = text2path(params["path"])
+			if(!ispath(to_evolve_path))
+				CRASH("Cortical borer attempted to evolve with a non-evolution path! (Got: [to_evolve_path])")
+
+			if(initial(to_evolve_path.evo_cost) > cortical_owner.stat_evolution)
+				return
+			if(initial(to_evolve_path.mutually_exclusive) && cortical_owner.genome_locked)
+				return
+			if(!cortical_owner.do_evolution(to_evolve_path))
+				return
+
+			log_borer_evolution("[key_name(owner)] gained knowledge: [initial(to_evolve_path.name)]")
+			cortical_owner.stat_evolution -= initial(to_evolve_path.evo_cost)
+			return TRUE
+
+/datum/action/cooldown/borer/evolution_tree/ui_state(mob/user)
+	return GLOB.always_state
+
+
 /datum/action/cooldown/borer/learn_focus
 	name = "Learn Focus"
 	button_icon_state = "getfocus"
@@ -183,7 +279,7 @@
 	cortical_owner.blood_chems_learned++
 	var/obj/item/organ/internal/brain/victim_brain = cortical_owner.human_host.getorganslot(ORGAN_SLOT_BRAIN)
 	if(victim_brain)
-		cortical_owner.human_host.adjustOrganLoss(ORGAN_SLOT_BRAIN, 5)
+		cortical_owner.human_host.adjustOrganLoss(ORGAN_SLOT_BRAIN, 5 * cortical_owner.host_harm_multiplier)
 	if(cortical_owner.blood_chems_learned == 5)
 		GLOB.successful_blood_chem += 1
 	owner.balloon_alert(owner, "[initial(reagent_choice.name)] learned")
@@ -223,7 +319,7 @@
 	cortical_owner.potential_chemicals -= reagent_choice
 	var/obj/item/organ/internal/brain/victim_brain = cortical_owner.human_host.getorganslot(ORGAN_SLOT_BRAIN)
 	if(victim_brain)
-		cortical_owner.human_host.adjustOrganLoss(ORGAN_SLOT_BRAIN, 5)
+		cortical_owner.human_host.adjustOrganLoss(ORGAN_SLOT_BRAIN, 5 * cortical_owner.host_harm_multiplier)
 	owner.balloon_alert(owner, "[initial(reagent_choice.name)] learned")
 	to_chat(cortical_owner.human_host, span_notice("You get a strange aftertaste of [initial(reagent_choice.taste_description)]!"))
 	StartCooldown()
@@ -248,14 +344,14 @@
 		owner.balloon_alert(owner, "1 stat evolution point required")
 		return
 	cortical_owner.stat_evolution--
-	cortical_owner.maxHealth += 5
-	cortical_owner.health_regen += 0.02
-	cortical_owner.max_chemical_storage += 20
-	cortical_owner.chemical_regen++
+	cortical_owner.maxHealth += cortical_owner.health_per_level
+	cortical_owner.health_regen += cortical_owner.health_regen_per_level
+	cortical_owner.max_chemical_storage += cortical_owner.chem_storage_per_level
+	cortical_owner.chemical_regen += cortical_owner.chem_regen_per_level
 	var/obj/item/organ/internal/brain/victim_brain = cortical_owner.human_host.getorganslot(ORGAN_SLOT_BRAIN)
 	if(victim_brain)
-		cortical_owner.human_host.adjustOrganLoss(ORGAN_SLOT_BRAIN, 10)
-	cortical_owner.human_host.adjust_blurriness(3) //about 12 seconds' worth
+		cortical_owner.human_host.adjustOrganLoss(ORGAN_SLOT_BRAIN, 10 * cortical_owner.host_harm_multiplier)
+	cortical_owner.human_host.adjust_blurriness(3 * cortical_owner.host_harm_multiplier) //about 12 seconds' worth by default
 	to_chat(cortical_owner, span_notice("You have grown!"))
 	to_chat(cortical_owner.human_host, span_warning("You feel a sharp pressure in your head!"))
 	StartCooldown()
@@ -269,11 +365,14 @@
 	. = ..()
 	if(!.)
 		return FALSE
+	var/mob/living/simple_animal/cortical_borer/cortical_owner = owner
 	if(owner.layer == PROJECTILE_HIT_THRESHHOLD_LAYER)
+		cortical_owner.upgrade_flags &= ~BORER_HIDING
 		owner.balloon_alert(owner, "stopped hiding")
 		owner.layer = BELOW_MOB_LAYER
 		StartCooldown()
 		return
+	cortical_owner.upgrade_flags |= BORER_HIDING
 	owner.balloon_alert(owner, "started hiding")
 	owner.layer = PROJECTILE_HIT_THRESHHOLD_LAYER
 	StartCooldown()
@@ -377,7 +476,8 @@
 			owner.balloon_alert(owner, "cannot function with sugar in host")
 			return
 		owner.balloon_alert(owner, "detached from host")
-		to_chat(cortical_owner.human_host, span_notice("Something carefully tickles your inner ear..."))
+		if(!(cortical_owner.upgrade_flags & BORER_STEALTH_MODE))
+			to_chat(cortical_owner.human_host, span_notice("Something carefully tickles your inner ear..."))
 		var/obj/item/organ/internal/borer_body/borer_organ = locate() in cortical_owner.human_host.internal_organs
 		//log the interaction
 		var/turf/human_turfone = get_turf(cortical_owner.human_host)
@@ -419,7 +519,7 @@
 		if(singular_host.has_borer())
 			owner.balloon_alert(owner, "target already occupied")
 			return
-		if(!do_after(cortical_owner, 6 SECONDS, target = singular_host))
+		if(!do_after(cortical_owner, ((cortical_owner.upgrade_flags & BORER_FAST_BORING) && (cortical_owner.upgrade_flags & BORER_HIDING) ? 3 SECONDS : 6 SECONDS), target = singular_host))
 			owner.balloon_alert(owner, "you and target must be still")
 			return
 		if(get_dist(singular_host, cortical_owner) > 1)
@@ -427,7 +527,8 @@
 			return
 		cortical_owner.human_host = singular_host
 		cortical_owner.forceMove(cortical_owner.human_host)
-		to_chat(cortical_owner.human_host, span_notice("A chilling sensation goes down your spine..."))
+		if(!(cortical_owner.upgrade_flags & BORER_STEALTH_MODE))
+			to_chat(cortical_owner.human_host, span_notice("A chilling sensation goes down your spine..."))
 		cortical_owner.copy_languages(cortical_owner.human_host)
 		var/obj/item/organ/internal/borer_body/borer_organ = new(cortical_owner.human_host)
 		borer_organ.borer = owner
@@ -448,7 +549,7 @@
 	if(choosen_human.has_borer())
 		owner.balloon_alert(owner, "target already occupied")
 		return
-	if(!do_after(cortical_owner, 6 SECONDS, target = choose_host))
+	if(!do_after(cortical_owner, ((cortical_owner.upgrade_flags & BORER_FAST_BORING) && (cortical_owner.upgrade_flags & BORER_HIDING) ? 3 SECONDS : 6 SECONDS), target = choose_host))
 		owner.balloon_alert(owner, "you and target must be still")
 		return
 	if(get_dist(choose_host, cortical_owner) > 1)
@@ -494,7 +595,7 @@
 	to_chat(cortical_host, span_boldwarning("Your voice moves without your permission!"))
 	var/obj/item/organ/internal/brain/victim_brain = cortical_owner.human_host.getorganslot(ORGAN_SLOT_BRAIN)
 	if(victim_brain)
-		cortical_owner.human_host.adjustOrganLoss(ORGAN_SLOT_BRAIN, 2)
+		cortical_owner.human_host.adjustOrganLoss(ORGAN_SLOT_BRAIN, 2 * cortical_owner.host_harm_multiplier)
 	cortical_host.say(message = borer_message, forced = TRUE)
 	var/turf/human_turf = get_turf(cortical_owner.human_host)
 	var/logging_text = "[key_name(cortical_owner)] forced [key_name(cortical_owner.human_host)] to say [borer_message] at [loc_name(human_turf)]"
@@ -513,22 +614,21 @@
 	if(!.)
 		return FALSE
 	var/mob/living/simple_animal/cortical_borer/cortical_owner = owner
-	if(!cortical_owner.inside_human())
+	if(!(cortical_owner.upgrade_flags & BORER_ALONE_PRODUCTION) && !cortical_owner.inside_human())
 		owner.balloon_alert(owner, "host required")
 		return
 	if(cortical_owner.chemical_storage < 100)
 		owner.balloon_alert(owner, "100 chemical points required")
 		return
 	cortical_owner.chemical_storage -= 100
-	var/turf/borer_turf = get_turf(cortical_owner)
-	var/obj/effect/mob_spawn/ghost_role/borer_egg/spawned_egg = new /obj/effect/mob_spawn/ghost_role/borer_egg(borer_turf)
-	spawned_egg.generation = (cortical_owner.generation + 1)
-	cortical_owner.children_produced++
-	if(cortical_owner.children_produced == GLOB.objective_egg_egg_number)
-		GLOB.successful_egg_number += 1
+	if((cortical_owner.upgrade_flags & BORER_ALONE_PRODUCTION) && !cortical_owner.inside_human())
+		no_host_egg()
+		StartCooldown()
+		return
+	produce_egg()
 	var/obj/item/organ/internal/brain/victim_brain = cortical_owner.human_host.getorganslot(ORGAN_SLOT_BRAIN)
 	if(victim_brain)
-		cortical_owner.human_host.adjustOrganLoss(ORGAN_SLOT_BRAIN, 25)
+		cortical_owner.human_host.adjustOrganLoss(ORGAN_SLOT_BRAIN, 25 * cortical_owner.host_harm_multiplier)
 		var/eggroll = rand(1,100)
 		if(eggroll <= 75)
 			switch(eggroll)
@@ -541,6 +641,7 @@
 				if(72 to 75)
 					cortical_owner.human_host.gain_trauma_type(BRAIN_TRAUMA_SEVERE, TRAUMA_RESILIENCE_LOBOTOMY)
 	to_chat(cortical_owner.human_host, span_warning("Your brain begins to hurt..."))
+	var/turf/borer_turf = get_turf(cortical_owner)
 	new /obj/effect/decal/cleanable/vomit(borer_turf)
 	playsound(borer_turf, 'sound/effects/splat.ogg', 50, TRUE)
 	var/logging_text = "[key_name(cortical_owner)] gave birth at [loc_name(borer_turf)]"
@@ -548,6 +649,26 @@
 	owner.balloon_alert(owner, "egg laid")
 	StartCooldown()
 
+/datum/action/cooldown/borer/produce_offspring/proc/no_host_egg()
+	var/mob/living/simple_animal/cortical_borer/cortical_owner = owner
+	cortical_owner.health = max(cortical_owner.health, 1, cortical_owner.health -= OUT_OF_HOST_EGG_COST)
+	produce_egg()
+	var/turf/borer_turf = get_turf(cortical_owner)
+	new/obj/effect/decal/cleanable/blood/splatter(borer_turf)
+	playsound(borer_turf, 'sound/effects/splat.ogg', 50, TRUE)
+	var/logging_text = "[key_name(cortical_owner)] gave birth alone at [loc_name(borer_turf)]"
+	cortical_owner.log_message(logging_text, LOG_GAME)
+	owner.balloon_alert(owner, "egg laid")
+
+/datum/action/cooldown/borer/produce_offspring/proc/produce_egg()
+	var/mob/living/simple_animal/cortical_borer/cortical_owner = owner
+	var/turf/borer_turf = get_turf(cortical_owner)
+	var/obj/effect/mob_spawn/ghost_role/borer_egg/spawned_egg = new /obj/effect/mob_spawn/ghost_role/borer_egg(borer_turf)
+	spawned_egg.generation = (cortical_owner.generation + 1)
+	cortical_owner.children_produced++
+	if(cortical_owner.children_produced == GLOB.objective_egg_egg_number)
+		GLOB.successful_egg_number += 1
+
 //revive your host
 /datum/action/cooldown/borer/revive_host
 	name = "Revive Host (200 chemicals)"
@@ -590,82 +711,6 @@
 	cortical_owner.human_host.log_message(logging_text, LOG_GAME)
 	StartCooldown()
 
-//certain abilities are now locked, you have to learn them
-/datum/action/cooldown/borer/learn_ability
-	name = "Learn Ability (2 stat points)"
-	button_icon_state = "newability"
-
-/datum/action/cooldown/borer/learn_ability/Trigger(trigger_flags)
-	. = ..()
-	if(!.)
-		return FALSE
-	var/mob/living/simple_animal/cortical_borer/cortical_owner = owner
-	if(!cortical_owner.inside_human())
-		owner.balloon_alert(owner, "host required")
-		return
-	if(cortical_owner.host_sugar())
-		owner.balloon_alert(owner, "cannot function with sugar in host")
-		return
-	if(cortical_owner.stat_evolution < 2)
-		owner.balloon_alert(owner, "2 stat points required")
-		return
-	cortical_owner.stat_evolution -= 2
-	var/list/abil_list = list("Produce Offspring", "Learn Chemical from Blood", "Revive Host", "Willing Host", "Upgrade Injection")
-	for(var/ability in abil_list)
-		switch(ability)
-			if("Produce Offspring")
-				if(locate(/datum/action/cooldown/borer/produce_offspring) in cortical_owner.known_abilities)
-					abil_list.Remove("Produce Offspring")
-			if("Learn Chemical from Blood")
-				if(locate(/datum/action/cooldown/borer/learn_bloodchemical) in cortical_owner.known_abilities)
-					abil_list.Remove("Learn Chemical from Blood")
-			if("Revive Host")
-				if(locate(/datum/action/cooldown/borer/revive_host) in cortical_owner.known_abilities)
-					abil_list.Remove("Revive Host")
-			if("Willing Host")
-				if(locate(/datum/action/cooldown/borer/willing_host) in cortical_owner.known_abilities)
-					abil_list.Remove("Willing Host")
-			if("Upgrade Injection")
-				if(length(cortical_owner.injection_rates_unlocked) >= length(cortical_owner.injection_rates))
-					abil_list.Remove("Upgrade Injection")
-	if(!length(abil_list))
-		owner.balloon_alert(owner, "all abilites learned")
-		cortical_owner.stat_evolution += 2
-		return
-	var/ability_choice = tgui_input_list(cortical_owner, "Choose your ability!", "Ability Choice", abil_list)
-	if(!ability_choice)
-		owner.balloon_alert(owner, "ability not selected")
-		cortical_owner.stat_evolution += 2
-		return
-	owner.balloon_alert(owner, "ability learned")
-	switch(ability_choice)
-		if("Produce Offspring")
-			var/datum/action/attack_action = new /datum/action/cooldown/borer/produce_offspring()
-			attack_action.Grant(cortical_owner)
-			cortical_owner.known_abilities += /datum/action/cooldown/borer/produce_offspring
-			return
-		if("Learn Chemical from Blood")
-			var/datum/action/attack_action = new /datum/action/cooldown/borer/learn_bloodchemical()
-			attack_action.Grant(cortical_owner)
-			cortical_owner.known_abilities += /datum/action/cooldown/borer/learn_bloodchemical
-			return
-		if("Revive Host")
-			var/datum/action/attack_action = new /datum/action/cooldown/borer/revive_host()
-			attack_action.Grant(cortical_owner)
-			cortical_owner.known_abilities += /datum/action/cooldown/borer/revive_host
-			return
-		if("Willing Host")
-			var/datum/action/attack_action = new /datum/action/cooldown/borer/willing_host()
-			attack_action.Grant(cortical_owner)
-			cortical_owner.known_abilities += /datum/action/cooldown/borer/willing_host
-			return
-		if("Upgrade Injection")
-			if(length(cortical_owner.injection_rates_unlocked) >= length(cortical_owner.injection_rates)) // Extra insurance
-				owner.balloon_alert(owner, "injection already maximized")
-				return
-			cortical_owner.injection_rates_unlocked += cortical_owner.injection_rates[length(cortical_owner.injection_rates_unlocked) + 1]
-	StartCooldown()
-
 //to ask if a host is willing
 /datum/action/cooldown/borer/willing_host
 	name = "Willing Host (150 chemicals)"
@@ -702,5 +747,67 @@
 	GLOB.willing_hosts += cortical_owner.human_host.ckey
 	StartCooldown()
 
+/datum/action/cooldown/borer/stealth_mode
+	name = "Stealth Mode (100 chemicals)"
+	cooldown_time = 2 MINUTES
+	button_icon_state = "willing"
+
+/datum/action/cooldown/borer/stealth_mode/Trigger(trigger_flags)
+	. = ..()
+	if(!.)
+		return FALSE
+	var/mob/living/simple_animal/cortical_borer/cortical_owner = owner
+	if(cortical_owner.host_sugar())
+		owner.balloon_alert(owner, "cannot function with sugar in host")
+		return
+	if(cortical_owner.chemical_storage < 100)
+		owner.balloon_alert(owner, "100 chemical points required")
+		return
+	var/in_stealth = (cortical_owner.upgrade_flags & BORER_STEALTH_MODE)
+	owner.balloon_alert(owner, "stealth mode [in_stealth ? "disabled" : "enabled"]")
+	if(in_stealth)
+		cortical_owner.upgrade_flags &= ~BORER_STEALTH_MODE
+	else
+		cortical_owner.upgrade_flags |= BORER_STEALTH_MODE
+
+
+	StartCooldown()
+
+/datum/action/cooldown/borer/empowered_offspring
+	name = "Produce Empowered Offspring (150 chemicals)"
+	cooldown_time = 1 MINUTES
+	button_icon_state = "reproduce"
+
+/datum/action/cooldown/borer/produce_offspring/Trigger(trigger_flags)
+	. = ..()
+	if(!.)
+		return FALSE
+	var/mob/living/simple_animal/cortical_borer/cortical_owner = owner
+	if(!cortical_owner.inside_human())
+		owner.balloon_alert(owner, "host required")
+		return
+	if(cortical_owner.stat != DEAD)
+		owner.balloon_alert(owner, "host not dead")
+		return
+	if(cortical_owner.chemical_storage < 150)
+		owner.balloon_alert(owner, "150 chemical points required")
+		return
+	cortical_owner.chemical_storage -= 150
+	var/turf/borer_turf = get_turf(cortical_owner)
+	var/obj/item/bodypart/chest/chest = cortical_owner.get_bodypart(BODY_ZONE_CHEST)
+	if((!chest || IS_ORGANIC_LIMB(chest)) && !cortical_owner.getorgan(/obj/item/organ/internal/empowered_borer_egg))
+		var/obj/item/organ/internal/empowered_borer_egg/spawned_egg = new(cortical_owner)
+		spawned_egg.generation = (cortical_owner.generation + 1)
+	cortical_owner.children_produced++
+	if(cortical_owner.children_produced == GLOB.objective_egg_egg_number)
+		GLOB.successful_egg_number += 1
+
+	playsound(borer_turf, 'sound/effects/splat.ogg', 50, TRUE)
+	var/logging_text = "[key_name(cortical_owner)] gave birth to an empowered borer at [loc_name(borer_turf)]"
+	cortical_owner.log_message(logging_text, LOG_GAME)
+	owner.balloon_alert(owner, "egg laid")
+	StartCooldown()
+
 #undef CHEMICALS_PER_UNIT
 #undef CHEMICAL_SECOND_DIVISOR
+#undef OUT_OF_HOST_EGG_COST

modular_skyrat/modules/cortical_borer/code/cortical_borer_egg.dm

@@ -22,7 +22,7 @@
 	///what the generation of the borer egg is
 	var/generation = 1
 	///the egg that is attached to this mob spawn
-	var/obj/item/borer_egg/host_egg
+	var/obj/item/borer_egg/host_egg = /obj/item/borer_egg
 
 /obj/effect/mob_spawn/ghost_role/borer_egg/Destroy()
 	host_egg = null
@@ -36,7 +36,7 @@
 
 /obj/effect/mob_spawn/ghost_role/borer_egg/Initialize(mapload, datum/team/cortical_borers/borer_team)
 	. = ..()
-	host_egg = new /obj/item/borer_egg(get_turf(src))
+	host_egg = new host_egg(get_turf(src))
 	host_egg.host_spawner = src
 	forceMove(host_egg)
 	var/area/src_area = get_area(src)
@@ -73,6 +73,10 @@
 	QDEL_NULL(host_spawner)
 	qdel(src)
 
+/obj/item/borer_egg/empowered
+	name = "empowered borer egg"
+	icon_state = "empowered_brainegg"
+
 /datum/uplink_item/dangerous/cortical_borer
 	name = "Cortical Borer Egg"
 	desc = "The egg of a cortical borer. The cortical borer is a parasite that can produce chemicals upon command, as well as \
@@ -88,3 +92,9 @@
 
 /obj/effect/mob_spawn/ghost_role/borer_egg/opfor
 	prompt_name = "cortical borer (OPFOR spawned)"
+
+/obj/effect/mob_spawn/ghost_role/borer_egg/empowered
+	name = "empowered borer egg"
+	desc = "An egg of a creature that came crawling out of someone instead of into them."
+	mob_type = /mob/living/simple_animal/cortical_borer/empowered
+	host_egg = /obj/item/borer_egg/empowered

modular_skyrat/modules/cortical_borer/code/evolution/borer_evolution.dm

@@ -0,0 +1,18 @@
+
+/mob/living/simple_animal/cortical_borer/proc/get_possible_evolutions()
+	var/list/possible_evolutions = list()
+	for(var/evolution_index in past_evolutions)
+		var/datum/borer_evolution/evolution = past_evolutions[evolution_index]
+		possible_evolutions |= evolution.unlocked_evolutions
+	return possible_evolutions
+
+/mob/living/simple_animal/cortical_borer/proc/do_evolution(datum/borer_evolution/evolution_type)
+	if(!ispath(evolution_type))
+		stack_trace("[type] do_evolution was given an invalid path! (Got: [evolution_type])")
+		return FALSE
+	if(past_evolutions[evolution_type])
+		return FALSE
+	var/datum/borer_evolution/initialized_evolution = new evolution_type()
+	past_evolutions[evolution_type] = initialized_evolution
+	initialized_evolution.on_evolve(src)
+	return TRUE

modular_skyrat/modules/cortical_borer/code/evolution/evolution_datum.dm

@@ -0,0 +1,39 @@
+/datum/borer_evolution
+	/// Name of the evolution
+	var/name = ""
+	/// Description of the evolution
+	var/desc = ""
+	/// Cost to get the evolution
+	var/evo_cost = 2 // T5 cost 3 points instead of 2
+	/// Text to show the borer when they evolve
+	var/gain_text = ""
+	/// What evolution genome this is
+	var/evo_type = BORER_EVOLUTION_GENERAL
+	/// If TRUE, this is an evolution that locks out other evolutions of the same tier & above but in different genomes
+	var/mutually_exclusive = FALSE
+	/// What evolutions this one unlocks
+	var/list/unlocked_evolutions = list()
+	/// What numerical tier is this? (Doesn't affect anything mechanically)
+	var/tier = 0
+
+/// What happens when a borer gets this evolution
+/datum/borer_evolution/proc/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	SHOULD_CALL_PARENT(TRUE)
+	if(gain_text)
+		to_chat(cortical_owner, span_notice(span_italics(gain_text)))
+	if(mutually_exclusive)
+		cortical_owner.genome_locked = TRUE
+
+/datum/borer_evolution/base
+	name = "The Beginning"
+	desc = "The start of a great age."
+	gain_text = "The worms, which we came to call \"Cortical Borers\", are fascinating creatures."
+	evo_cost = 0
+	evo_type = BORER_EVOLUTION_START
+	tier = 0
+	unlocked_evolutions = list(
+		/datum/borer_evolution/upgrade_injection,
+		/datum/borer_evolution/symbiote/willing_host,
+		/datum/borer_evolution/hivelord/produce_offspring,
+		/datum/borer_evolution/diveworm/health_per_level,
+	)

modular_skyrat/modules/cortical_borer/code/evolution/evolution_diveworm.dm

@@ -0,0 +1,108 @@
+/datum/borer_evolution/diveworm
+	evo_type = BORER_EVOLUTION_DIVEWORM
+
+// T1
+/datum/borer_evolution/diveworm/health_per_level
+	name = "Health Increase"
+	desc = "Increase the amount of health per level-up you gain."
+	gain_text = "Over time, some of the more aggressive worms became harder to dissect post-mortem. Their skin membrane has become up to thrice as thick."
+	tier = 1
+	unlocked_evolutions = list(/datum/borer_evolution/diveworm/host_speed)
+
+/datum/borer_evolution/diveworm/health_per_level/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	cortical_owner.health_per_level += 2.5
+	cortical_owner.recalculate_stats()
+
+// T2
+/datum/borer_evolution/diveworm/host_speed
+	name = "Boring Speed"
+	desc = "Decrease the time it takes to enter a host when you are not hiding."
+	gain_text = "Once or twice, I would blink, and see the non-host monkeys be grappling with a worm that was cross the room just moments before."
+	tier = 2
+	unlocked_evolutions = list(/datum/borer_evolution/diveworm/expanded_chemicals)
+
+/datum/borer_evolution/diveworm/host_speed/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	cortical_owner.upgrade_flags |= BORER_FAST_BORING
+
+// T3 + T1 path
+/datum/borer_evolution/diveworm/expanded_chemicals
+	name = "Expanded Chemical List"
+	desc = "Gain access to a new list of devious chemicals to the unlockable list."
+	gain_text = "Sometimes, I would just see a known host monkey... collapse, then get up, then collapse again. It was as if the worm was playing with it..."
+	mutually_exclusive = TRUE
+	tier = 3
+	unlocked_evolutions = list(
+		/datum/borer_evolution/diveworm/harm_increase,
+		/datum/borer_evolution/diveworm/health_per_level/t2,
+	)
+	var/static/list/added_chemicals = list(
+		/datum/reagent/toxin/fentanyl,
+		/datum/reagent/toxin/staminatoxin,
+		/datum/reagent/toxin/mutetoxin,
+		/datum/reagent/toxin/mutagen,
+		/datum/reagent/toxin/cyanide,
+		/datum/reagent/drug/opium,
+		/datum/reagent/drug/mushroomhallucinogen,
+		/datum/reagent/inverse/oculine,
+	)
+
+/datum/borer_evolution/diveworm/expanded_chemicals/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	cortical_owner.potential_chemicals |= added_chemicals
+
+/datum/borer_evolution/diveworm/health_per_level/t2
+	name = "Health Increase II"
+	tier = -1
+	unlocked_evolutions = list(/datum/borer_evolution/diveworm/health_per_level/t3)
+
+/datum/borer_evolution/diveworm/health_per_level/t3
+	name = "Health Increase III"
+	tier = -1
+	unlocked_evolutions = list()
+
+// T4 + its path
+/datum/borer_evolution/diveworm/harm_increase
+	name = "Toxins Increase"
+	desc = "Increase the passive and active damage you do to your host, and how often it occurs."
+	gain_text = "In captivity, some of the worms became more... brutish, larger. Most notably, hosts succumbed much quicker to them."
+	tier = 4
+	unlocked_evolutions = list(
+		/datum/borer_evolution/diveworm/harm_increase/t2,
+		/datum/borer_evolution/diveworm/empowered_offspring,
+	)
+
+/datum/borer_evolution/diveworm/harm_increase/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	cortical_owner.host_harm_multiplier += 0.25
+
+/datum/borer_evolution/diveworm/harm_increase/t2
+	name = "Toxins Increase II"
+	desc = "Further increase the passive and active damage you do to your host, and how often it occurs."
+	tier = -1
+	unlocked_evolutions = list(/datum/borer_evolution/diveworm/harm_increase/t3)
+
+/datum/borer_evolution/diveworm/harm_increase/t3
+	name = "Toxins Increase III"
+	desc = "Further increase the passive and active damage you do to your host, and how often it occurs."
+	tier = -1
+	unlocked_evolutions = list()
+
+// T5
+/datum/borer_evolution/diveworm/empowered_offspring
+	name = "Empowered Offspring"
+	desc = "Lay an egg in a deceased host, and after a delay an empowered borer will burst out."
+	gain_text = "Most eggs would be regurgitated through the throat from their hosts... but one did not. They exploded out the chest like a horror movie. What a worrying discovery."
+	evo_cost = 3
+	tier = 5
+	unlocked_evolutions = list(
+		/datum/borer_evolution/sugar_immunity,
+		/datum/borer_evolution/synthetic_borer,
+		/datum/borer_evolution/synthetic_chems_negative,
+	)
+
+/datum/borer_evolution/diveworm/empowered_offspring/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	var/datum/action/cooldown/borer/learn_bloodchemical/attack_action = new()
+	attack_action.Grant(cortical_owner)

modular_skyrat/modules/cortical_borer/code/evolution/evolution_general.dm

@@ -0,0 +1,82 @@
+/datum/borer_evolution/upgrade_injection
+	name = "Upgrade Injection"
+	desc = "Upgrade your possible injection amount to 10 units."
+	gain_text = "Their growth is astounding, their organs and glands can expand several times their size in mere days."
+	unlocked_evolutions = list(/datum/borer_evolution/upgrade_injection/t2)
+	tier = 1
+
+/datum/borer_evolution/upgrade_injection/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	cortical_owner.injection_rates_unlocked += cortical_owner.injection_rates[length(cortical_owner.injection_rates_unlocked) + 1]
+
+/datum/borer_evolution/upgrade_injection/t2
+	name = "Upgrade Injection II"
+	desc = "Upgrade your possible injection amount to 25 units."
+	unlocked_evolutions = list(/datum/borer_evolution/upgrade_injection/t3)
+	tier = 2
+
+/datum/borer_evolution/upgrade_injection/t3
+	name = "Upgrade Injection III"
+	desc = "Upgrade your possible injection amount to 50 units."
+	unlocked_evolutions = list()
+	tier = 3
+
+/datum/borer_evolution/sugar_immunity
+	name = "Sugar Immunity"
+	desc = "Become immune to the ill effects of sugar in you or a host."
+	gain_text = "Of the biggest ones, a few have managed to resist the effects of sugar. Truly concerning if we wish to keep them contained."
+	evo_cost = 5
+	tier = 6
+
+/datum/borer_evolution/sugar_immunity/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	cortical_owner.upgrade_flags |= BORER_SUGAR_IMMUNE
+
+/datum/borer_evolution/synthetic_borer
+	name = "Synthetic Boring"
+	desc = "Gain the ability to take synthetic humans as a host as well."
+	gain_text = "Now, we used robots to take care of the worms when they're alive, but one day... they all went haywire. Security took them down, closer inspection showed that the worms managed their way into the processing units."
+	evo_cost = 6
+	tier = 6
+
+/datum/borer_evolution/synthetic_borer/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	cortical_owner.organic_restricted = FALSE
+
+/datum/borer_evolution/synthetic_chems_positive
+	name = "Synthetic Chemicals (+)"
+	desc = "Gain access to a list of helpful, synthetic-compatible chemicals."
+	gain_text = "Once we had established that robots weren't safe either, we began to experiment with them. Interestingly enough, some of them never needed to be oiled again."
+	tier = 6
+	evo_cost = 6
+	var/static/list/added_chemicals = list(
+		/datum/reagent/consumable/ethanol/synthanol,
+		/datum/reagent/medicine/system_cleaner,
+		/datum/reagent/medicine/nanite_slurry,
+		/datum/reagent/medicine/liquid_solder,
+		/datum/reagent/oil,
+		/datum/reagent/fuel,
+	)
+
+/datum/borer_evolution/synthetic_chems_positive/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	cortical_owner.potential_chemicals |= added_chemicals
+
+/datum/borer_evolution/synthetic_chems_negative
+	name = "Synthetic Chemicals (-)"
+	desc = "Gain access to a list of synthetic-damaging chemicals."
+	gain_text = "Good thing is, some of the worms were hostile to the robots, too. Corroded from the inside, some of them were basically husks."
+	tier = 6
+	evo_cost = 6
+	var/static/list/added_chemicals = list(
+		/datum/reagent/toxin/acid/fluacid, // More like anti everything but :shrug:
+		/datum/reagent/toxin/plasma,
+		/datum/reagent/teslium,
+		/datum/reagent/thermite,
+		/datum/reagent/pyrosium,
+		/datum/reagent/oxygen,
+	)
+
+/datum/borer_evolution/synthetic_chems_negative/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	cortical_owner.potential_chemicals |= added_chemicals

modular_skyrat/modules/cortical_borer/code/evolution/evolution_hivelord.dm

@@ -0,0 +1,72 @@
+/datum/borer_evolution/hivelord
+	evo_type = BORER_EVOLUTION_HIVELORD
+
+// T1
+/datum/borer_evolution/hivelord/produce_offspring
+	name = "Produce Offspring"
+	desc = "Produce an egg, which your host will vomit up."
+	gain_text = "The way that a Cortical Borer produces an egg is a strange one. So far, we have not seen how it produces one, or it doing so outside a host."
+	tier = 1
+	unlocked_evolutions = list(/datum/borer_evolution/hivelord/blood_chemical)
+
+/datum/borer_evolution/hivelord/produce_offspring/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	var/datum/action/cooldown/borer/produce_offspring/attack_action = new()
+	attack_action.Grant(cortical_owner)
+
+// T2
+/datum/borer_evolution/hivelord/blood_chemical
+	name = "Learn Blood Chemical"
+	desc = "Learn a synthesizable chemical from the blood of your host."
+	gain_text = "As we were dissecting a former host monkey's fecal matter, I noticed a high concentration of banana matter, despite us not feeding them any for the past week."
+	tier = 2
+	unlocked_evolutions = list(/datum/borer_evolution/hivelord/movespeed)
+
+/datum/borer_evolution/hivelord/blood_chemical/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	var/datum/action/cooldown/borer/learn_bloodchemical/attack_action = new()
+	attack_action.Grant(cortical_owner)
+
+// T3
+/datum/borer_evolution/hivelord/movespeed
+	name = "Increased Energy"
+	desc = "Boost your speed by a large amount."
+	gain_text = "And as I watched, the Cortical Borer was able to complete the course in just over half the time it had last week."
+	mutually_exclusive = TRUE
+	tier = 3
+	unlocked_evolutions = list(/datum/borer_evolution/hivelord/stealth_mode)
+
+/datum/borer_evolution/hivelord/movespeed/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	cortical_owner.add_movespeed_modifier(/datum/movespeed_modifier/borer_speed)
+
+// T4
+/datum/borer_evolution/hivelord/stealth_mode
+	name = "Stealth Mode"
+	desc = "While in stealth mode, your presence is much less noticable in hosts, but you do not gain passive benefits."
+	gain_text = "As I was writing my report one day, I noticed that one of the worms had slipped out of its cage and into a monkey without so much as a sound. Fascinating how they seem to know the importance of sound."
+	tier = 4
+	unlocked_evolutions = list(/datum/borer_evolution/hivelord/produce_offspring_alone)
+
+/datum/borer_evolution/hivelord/stealth_mode/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	var/datum/action/cooldown/borer/stealth_mode/attack_action = new()
+	attack_action.Grant(cortical_owner)
+
+// T5
+/datum/borer_evolution/hivelord/produce_offspring_alone
+	name = "Produce Offspring II"
+	desc = "Allows you to produce eggs outside a host, in exchange for health and chemicals."
+	gain_text = "One of the worms seems to have taken an... Alpha position in the hive, producing more eggs than the others. Most worryingly, eggs have shown up without them having a host, but I haven't *seen* them lay any..."
+	evo_cost = 3
+	tier = 5
+	unlocked_evolutions = list(
+		/datum/borer_evolution/sugar_immunity,
+		/datum/borer_evolution/synthetic_borer,
+		/datum/borer_evolution/synthetic_chems_positive,
+		/datum/borer_evolution/synthetic_chems_negative,
+	)
+
+/datum/borer_evolution/hivelord/produce_offspring_alone/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	cortical_owner.upgrade_flags |= BORER_ALONE_PRODUCTION

modular_skyrat/modules/cortical_borer/code/evolution/evolution_symbiote.dm

@@ -0,0 +1,111 @@
+/datum/borer_evolution/symbiote
+	evo_type = BORER_EVOLUTION_SYMBIOTE
+
+// T1
+/datum/borer_evolution/symbiote/willing_host
+	name = "Willing Host"
+	desc = "Ask a host if they are willing, furthering your objectives."
+	gain_text = "Some of the monkeys we gave the worms seemed far more... willing than others to be a host. I could've sworn one let them climb up their arm."
+	tier = 1
+	unlocked_evolutions = list(/datum/borer_evolution/symbiote/chem_per_level)
+
+/datum/borer_evolution/symbiote/willing_host/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	var/datum/action/cooldown/borer/willing_host/attack_action = new()
+	attack_action.Grant(cortical_owner)
+
+// T2
+/datum/borer_evolution/symbiote/chem_per_level
+	name = "Chemical Increase"
+	desc = "Increase the amount of chemicals per level-up you gain."
+	gain_text = "The rate of which we've had to clean the borer pens is increasing. Perhaps their secretions are excess chemicals they cannot use?"
+	tier = 2
+	unlocked_evolutions = list(/datum/borer_evolution/symbiote/expanded_chemicals)
+
+/datum/borer_evolution/symbiote/chem_per_level/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	cortical_owner.chem_storage_per_level += 10
+	cortical_owner.chem_regen_per_level += 0.5
+	cortical_owner.recalculate_stats()
+
+// T3 + T2 Path
+/datum/borer_evolution/symbiote/expanded_chemicals
+	name = "Expanded Chemical List"
+	desc = "Gain access to a new list of helpful chemicals to the unlockable list."
+	gain_text = "The chemicals the worms seem capable of synthesizing are truly remarkable, their hosts are able to get up from amazing amounts of harm."
+	mutually_exclusive = TRUE
+	tier = 3
+	unlocked_evolutions = list(
+		/datum/borer_evolution/symbiote/harm_decrease,
+		/datum/borer_evolution/symbiote/chem_per_level/t2,
+	)
+	var/static/list/added_chemicals = list(
+		/datum/reagent/medicine/sal_acid,
+		/datum/reagent/medicine/oxandrolone,
+		/datum/reagent/medicine/atropine,
+		/datum/reagent/medicine/neurine,
+		/datum/reagent/medicine/leporazine,
+		/datum/reagent/medicine/omnizine,
+	)
+
+/datum/borer_evolution/symbiote/expanded_chemicals/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	cortical_owner.potential_chemicals |= added_chemicals
+
+/datum/borer_evolution/symbiote/chem_per_level/t2
+	name = "Chemical Increase II"
+	desc = "Increase the amount of chemicals per level-up you gain even further."
+	tier = -1
+	unlocked_evolutions = list(/datum/borer_evolution/symbiote/chem_per_level/t3)
+
+/datum/borer_evolution/symbiote/chem_per_level/t3
+	name = "Chemical Increase III"
+	desc = "Increase the amount of chemicals per level-up you gain even further."
+	tier = -1
+	unlocked_evolutions = list()
+
+// T4 and path
+/datum/borer_evolution/symbiote/harm_decrease
+	name = "Toxins Decrease"
+	desc = "Decrease the passive and active damage you do to your host, and how often it occurs."
+	gain_text = "However, some of the others became... if not smaller, certainly longer, more lithe."
+	tier = 4
+	unlocked_evolutions = list(
+		/datum/borer_evolution/symbiote/harm_decrease/t2,
+		/datum/borer_evolution/symbiote/revive_host,
+	)
+
+/datum/borer_evolution/symbiote/harm_decrease/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	cortical_owner.host_harm_multiplier -= 0.25
+
+/datum/borer_evolution/symbiote/harm_decrease/t2
+	name = "Toxins Decrease II"
+	desc = "Further decrease the passive and active damage you do to your host, and how often it occurs."
+	tier = -1
+	unlocked_evolutions = list(/datum/borer_evolution/symbiote/harm_decrease/t3)
+
+/datum/borer_evolution/symbiote/harm_decrease/t3
+	name = "Toxins Decrease III"
+	desc = "Further decrease the passive and active damage you do to your host, and how often it occurs."
+	tier = -1
+	unlocked_evolutions = list()
+
+// T5
+/datum/borer_evolution/symbiote/revive_host
+	name = "Revive Host"
+	desc = "Revive your host and heal what ails them."
+	gain_text = "As I was in the lab, the most curious occurance so far happened. A Cortical Borer went into one of the cadaver's heads, and moments later they were standing again."
+	evo_cost = 3
+	tier = 5
+	unlocked_evolutions = list(
+		/datum/borer_evolution/sugar_immunity,
+		/datum/borer_evolution/synthetic_borer,
+		/datum/borer_evolution/synthetic_chems_positive,
+	)
+
+/datum/borer_evolution/symbiote/revive_host/on_evolve(mob/living/simple_animal/cortical_borer/cortical_owner)
+	. = ..()
+	var/datum/action/cooldown/borer/revive_host/attack_action = new()
+	attack_action.Grant(cortical_owner)
+

modular_skyrat/modules/cortical_borer/code/evolution/evolution_things/empowered_egg.dm

@@ -0,0 +1,52 @@
+/obj/item/organ/internal/empowered_borer_egg
+	name = "strange egg"
+	desc = "All slimy and yuck."
+	icon_state = "innards" // not like you'll be seeing this anyway
+	visual = TRUE
+	zone = BODY_ZONE_CHEST
+	slot = ORGAN_SLOT_PARASITE_EGG
+	/// How long it takes to burst from a corpse
+	var/burst_time = 3 MINUTES
+	/// What generation the egg will be
+	var/generation = 1
+
+/obj/item/organ/internal/empowered_borer_egg/on_find(mob/living/finder)
+	..()
+	to_chat(finder, span_warning("You found an unknown egg in [owner]'s [zone]!"))
+
+/obj/item/organ/internal/empowered_borer_egg/Initialize(mapload)
+	. = ..()
+	if(iscarbon(loc))
+		Insert(loc)
+
+/obj/item/organ/internal/empowered_borer_egg/Insert(mob/living/carbon/M, special = FALSE, drop_if_replaced = TRUE)
+	..()
+	addtimer(CALLBACK(src, .proc/try_burst), burst_time)
+
+/obj/item/organ/internal/empowered_borer_egg/Remove(mob/living/carbon/M, special = FALSE)
+	. = ..()
+	visible_message(span_warning(span_italics("As [src] is cut out of [M], it quickly vibrates and shatters, leaving nothing but some goop!")))
+	new/obj/effect/decal/cleanable/food/egg_smudge(get_turf(src))
+	qdel(src)
+
+/obj/item/organ/internal/empowered_borer_egg/proc/try_burst()
+	if(!owner)
+		qdel(src)
+		return
+	if(owner.stat != DEAD)
+		qdel(src)
+		return
+	var/list/candidates = poll_ghost_candidates("Do you want to spawn as an empowered Cortical Borer bursting from [owner]?", ROLE_PAI, FALSE, 10 SECONDS, POLL_IGNORE_CORTICAL_BORER)
+	if(!length(candidates))
+		var/obj/effect/mob_spawn/ghost_role/borer_egg/empowered/borer_egg = new(get_turf(owner))
+		borer_egg.generation = generation
+		var/obj/item/bodypart/chest/chest = owner.get_bodypart(BODY_ZONE_CHEST)
+		chest.dismember()
+		return
+	var/mob/dead/observer/new_borer = pick(candidates)
+	var/mob/living/simple_animal/cortical_borer/empowered/spawned_cb = new(get_turf(owner))
+	var/obj/item/bodypart/chest/chest = owner.get_bodypart(BODY_ZONE_CHEST)
+	chest.dismember()
+	spawned_cb.generation = generation
+	spawned_cb.ckey = new_borer.ckey
+	spawned_cb.mind.add_antag_datum(/datum/antagonist/cortical_borer)

modular_skyrat/modules/cortical_borer/code/focus_datum.dm

@@ -54,7 +54,7 @@
 
 /datum/borer_focus/arms/on_add(mob/living/carbon/human/host, mob/living/simple_animal/cortical_borer/borer)
 	to_chat(host, span_notice("Your arms start to feel funny..."))
-	borer.human_host.add_actionspeed_modifier(/datum/actionspeed_modifier/borer_speed)
+	borer.human_host.add_actionspeed_modifier(/datum/actionspeed_modifier/focus_speed)
 	return ..()
 
 /datum/borer_focus/arms/on_remove(mob/living/carbon/human/host, mob/living/simple_animal/cortical_borer/borer)
@@ -68,10 +68,10 @@
 
 /datum/borer_focus/legs/on_add(mob/living/carbon/human/host, mob/living/simple_animal/cortical_borer/borer)
 	to_chat(host, span_notice("You feel faster..."))
-	host.add_movespeed_modifier(/datum/movespeed_modifier/borer_speed)
+	host.add_movespeed_modifier(/datum/movespeed_modifier/focus_speed)
 	return ..()
 
 /datum/borer_focus/legs/on_remove(mob/living/carbon/human/host, mob/living/simple_animal/cortical_borer/borer)
 	to_chat(host, span_notice("You feel slower..."))
-	host.remove_movespeed_modifier(/datum/movespeed_modifier/borer_speed)
+	host.remove_movespeed_modifier(/datum/movespeed_modifier/focus_speed)
 	return ..()

tgstation.dme

@@ -5333,6 +5333,13 @@
 #include "modular_skyrat\modules\cortical_borer\code\cortical_borer_items.dm"
 #include "modular_skyrat\modules\cortical_borer\code\focus_datum.dm"
 #include "modular_skyrat\modules\cortical_borer\code\status_effects.dm"
+#include "modular_skyrat\modules\cortical_borer\code\evolution\borer_evolution.dm"
+#include "modular_skyrat\modules\cortical_borer\code\evolution\evolution_datum.dm"
+#include "modular_skyrat\modules\cortical_borer\code\evolution\evolution_diveworm.dm"
+#include "modular_skyrat\modules\cortical_borer\code\evolution\evolution_general.dm"
+#include "modular_skyrat\modules\cortical_borer\code\evolution\evolution_hivelord.dm"
+#include "modular_skyrat\modules\cortical_borer\code\evolution\evolution_symbiote.dm"
+#include "modular_skyrat\modules\cortical_borer\code\evolution\evolution_things\empowered_egg.dm"
 #include "modular_skyrat\modules\crafting\crafting_skyrat.dm"
 #include "modular_skyrat\modules\cryosleep\code\admin.dm"
 #include "modular_skyrat\modules\cryosleep\code\ai.dm"

tgui/packages/tgui/interfaces/BorerEvolution.tsx

@@ -0,0 +1,140 @@
+import { useBackend } from '../backend';
+import { Section, Stack, Button, BlockQuote } from '../components';
+import { Window } from '../layouts';
+
+const borerColor = {
+  fontWeight: 'bold',
+  color: '#b2c96b',
+};
+
+type Evolution = {
+  path: string;
+  name: string;
+  desc: string;
+  gainFlavor: string;
+  cost: number;
+  disabled: boolean;
+  evoPath: string;
+  color: string;
+  tier: number;
+  exclusive: boolean;
+};
+
+type EvolutionInfo = {
+  learnableEvolution: Evolution[];
+  learnedEvolution: Evolution[];
+};
+
+type Info = {
+  evolution_points: number;
+};
+
+export const BorerEvolution = (props, context) => {
+  return (
+    <Window width={675} height={600} theme="wizard" title="Evolution Tree">
+      <Window.Content>
+        <Stack vertical fill>
+          <Stack.Item grow>
+            <EvoInfo />
+          </Stack.Item>
+        </Stack>
+      </Window.Content>
+    </Window>
+  );
+};
+
+const PastEvolutions = (props, context) => {
+  const { data } = useBackend<EvolutionInfo>(context);
+  const { learnedEvolution } = data;
+
+  return (
+    <Stack.Item grow>
+      <Section title="Past Evolutions" fill scrollable>
+        <Stack vertical>
+          {(!learnedEvolution.length && 'None!') ||
+            learnedEvolution.map((learned) => (
+              <Stack.Item key={learned.name}>
+                <Button
+                  width="100%"
+                  color={learned.color}
+                  content={`${learned.evoPath} - ${
+                    learned.tier !== -1 ? `T${learned.tier} -` : ``
+                  } ${learned.name}`}
+                  tooltip={learned.desc}
+                />
+              </Stack.Item>
+            ))}
+        </Stack>
+      </Section>
+    </Stack.Item>
+  );
+};
+
+const EvolutionList = (props, context) => {
+  const { data, act } = useBackend<EvolutionInfo>(context);
+  const { learnableEvolution } = data;
+
+  return (
+    <Stack.Item grow>
+      <Section title="Possible Evolutions" fill scrollable>
+        {(!learnableEvolution.length && 'None!') ||
+          learnableEvolution.map((toLearn) => (
+            <Stack.Item key={toLearn.name} mb={1}>
+              <Button
+                width="100%"
+                color={toLearn.color}
+                disabled={toLearn.disabled}
+                content={`${toLearn.evoPath} - ${
+                  toLearn.tier !== -1 ? `T${toLearn.tier} -` : ``
+                } ${
+                  toLearn.cost > 0
+                    ? `${toLearn.name}: ${toLearn.cost}
+                  point${toLearn.cost !== 1 ? 's' : ''}`
+                    : toLearn.name
+                }`}
+                tooltip={
+                  toLearn.exclusive
+                    ? toLearn.desc +
+                    ` By taking this, you cannot take other T3+ gneomes.`
+                    : toLearn.desc
+                }
+                onClick={() => act('evolve', { path: toLearn.path })}
+              />
+              {!!toLearn.gainFlavor && (
+                <BlockQuote>
+                  <i>{toLearn.gainFlavor}</i>
+                </BlockQuote>
+              )}
+            </Stack.Item>
+          ))}
+      </Section>
+    </Stack.Item>
+  );
+};
+
+const EvoInfo = (props, context) => {
+  const { data } = useBackend<Info>(context);
+  const { evolution_points } = data;
+
+  return (
+    <Stack justify="space-evenly" height="100%" width="100%">
+      <Stack.Item grow>
+        <Stack vertical height="100%">
+          <Stack.Item fontSize="20px" textAlign="center">
+            You have <b>{evolution_points || 0}</b>&nbsp;
+            <span style={borerColor}>
+              evolution point{evolution_points !== 1 ? 's' : ''}
+            </span>{' '}
+            to spend.
+          </Stack.Item>
+          <Stack.Item grow>
+            <Stack height="100%">
+              <PastEvolutions />
+              <EvolutionList />
+            </Stack>
+          </Stack.Item>
+        </Stack>
+      </Stack.Item>
+    </Stack>
+  );
+};