really surprised this wasn't done earlier

code/__DEFINES/status_effects.dm

@@ -34,6 +34,8 @@
 
 #define STATUS_EFFECT_HIPPOCRATIC_OATH /datum/status_effect/hippocraticOath //Gives you an aura of healing as well as regrowing the Rod of Asclepius if lost
 
+#define STATUS_EFFECT_REGENERATIVE_CORE /datum/status_effect/regenerative_core	//removes damage slowdown while giving a slow regenerating effect
+
 /////////////
 // DEBUFFS //
 /////////////

code/__DEFINES/traits.dm

@@ -78,6 +78,7 @@
 #define TRAIT_MONKEYLIKE		"monkeylike" //sets IsAdvancedToolUser to FALSE
 #define TRAIT_PACIFISM			"pacifism"
 #define TRAIT_IGNORESLOWDOWN	"ignoreslow"
+#define TRAIT_IGNOREDAMAGESLOWDOWN "ignoredamageslowdown"
 #define TRAIT_DEATHCOMA			"deathcoma" //Causes death-like unconsciousness
 #define TRAIT_FAKEDEATH			"fakedeath" //Makes the owner appear as dead to most forms of medical examination
 #define TRAIT_DISFIGURED		"disfigured"
@@ -187,7 +188,7 @@
 #define TRAIT_NO_INTERNALS		"no-internals"
 #define TRAIT_NO_ALCOHOL		"alcohol_intolerance"
 #define TRAIT_MUTATION_STASIS			"mutation_stasis" //Prevents processed genetics mutations from processing.
-#define TRAIT_FAST_PUMP				"fast_pump"	
+#define TRAIT_FAST_PUMP				"fast_pump"
 
 // mobility flag traits
 // IN THE FUTURE, IT WOULD BE NICE TO DO SOMETHING SIMILAR TO https://github.com/tgstation/tgstation/pull/48923/files (ofcourse not nearly the same because I have my.. thoughts on it)

code/datums/status_effects/buffs.dm

@@ -550,3 +550,27 @@
 			else if(isanimal(L))
 				var/mob/living/simple_animal/SM = L
 				SM.adjustHealth(-3.5, forced = TRUE)
+
+/obj/screen/alert/status_effect/regenerative_core
+	name = "Reinforcing Tendrils"
+	desc = "You can move faster than your broken body could normally handle!"
+	icon_state = "regenerative_core"
+	name = "Regenerative Core Tendrils"
+
+/datum/status_effect/regenerative_core
+	id = "Regenerative Core"
+	duration = 1 MINUTES
+	status_type = STATUS_EFFECT_REPLACE
+	alert_type = /obj/screen/alert/status_effect/regenerative_core
+
+/datum/status_effect/regenerative_core/on_apply()
+	ADD_TRAIT(owner, TRAIT_IGNOREDAMAGESLOWDOWN, "regenerative_core")
+	owner.adjustBruteLoss(-25)
+	if(!AmBloodsucker(owner))	//use your coffin you lazy bastard
+		owner.adjustFireLoss(-25)
+	owner.remove_CC()
+	owner.bodytemperature = BODYTEMP_NORMAL
+	return TRUE
+
+/datum/status_effect/regenerative_core/on_remove()
+	REMOVE_TRAIT(owner, TRAIT_IGNOREDAMAGESLOWDOWN, "regenerative_core")

code/modules/mining/equipment/regenerative_core.dm

@@ -85,15 +85,12 @@
 		to_chat(user, "<span class='notice'>[src] are useless on the dead.</span>")
 		return
 	if(H != user)
-		H.visible_message("[user] forces [H] to apply [src]... [H.p_they()] quickly regenerate all injuries!")
+		H.visible_message("[user] forces [H] to apply [src]... Black tendrils entangle and reinforce [H.p_them()]!")
 		SSblackbox.record_feedback("nested tally", "hivelord_core", 1, list("[type]", "used", "other"))
 	else
-		to_chat(user, "<span class='notice'>You start to smear [src] on yourself. It feels and smells disgusting, but you feel amazingly refreshed in mere moments.</span>")
+		to_chat(user, "<span class='notice'>You start to smear [src] on yourself. Disgusting tendrils hold you together and allow you to keep moving, but for how long?</span>")
 		SSblackbox.record_feedback("nested tally", "hivelord_core", 1, list("[type]", "used", "self"))
-	if(AmBloodsucker(H))
+	H.apply_status_effect(STATUS_EFFECT_REGENERATIVE_CORE)
-		H.revive(full_heal = FALSE)
-	else
-		H.revive(full_heal = TRUE)
 	qdel(src)
 	user.log_message("[user] used [src] to heal [H == user ? "[H.p_them()]self" : H]! Wake the fuck up, Samurai!", LOG_ATTACK, color="green") //Logging for 'old' style legion core use, when clicking on a sprite of yourself or another.
 

code/modules/mob/living/carbon/human/human.dm

@@ -1049,15 +1049,16 @@
 /mob/living/carbon/human/updatehealth()
 	. = ..()
 
-	if(HAS_TRAIT(src, TRAIT_IGNORESLOWDOWN))
+	if(HAS_TRAIT(src, TRAIT_IGNORESLOWDOWN))	//if we want to ignore slowdown from damage and equipment
 		remove_movespeed_modifier(/datum/movespeed_modifier/damage_slowdown)
 		remove_movespeed_modifier(/datum/movespeed_modifier/damage_slowdown_flying)
 		return
 	var/stambufferinfluence = (bufferedstam*(100/stambuffer))*0.2 //CIT CHANGE - makes stamina buffer influence movedelay
-	var/health_deficiency = ((100 + stambufferinfluence) - health + (getStaminaLoss()*0.75))//CIT CHANGE - reduces the impact of staminaloss and makes stamina buffer influence it
+	if(!HAS_TRAIT(src, TRAIT_IGNOREDAMAGESLOWDOWN))	//if we want to ignore slowdown from damage, but not from equipment
-	if(health_deficiency >= 40)
+		var/health_deficiency = ((maxHealth + stambufferinfluence) - health + (getStaminaLoss()*0.75))//CIT CHANGE - reduces the impact of staminaloss and makes stamina buffer influence it
-		add_or_update_variable_movespeed_modifier(/datum/movespeed_modifier/damage_slowdown, TRUE, (health_deficiency-39) / 75)
+		if(health_deficiency >= 40)
-		add_or_update_variable_movespeed_modifier(/datum/movespeed_modifier/damage_slowdown_flying, TRUE, (health_deficiency-39) / 25)
+			add_or_update_variable_movespeed_modifier(/datum/movespeed_modifier/damage_slowdown, TRUE, (health_deficiency-39) / 75)
+			add_or_update_variable_movespeed_modifier(/datum/movespeed_modifier/damage_slowdown_flying, TRUE, (health_deficiency-39) / 25)
 	else
 		remove_movespeed_modifier(/datum/movespeed_modifier/damage_slowdown)
 		remove_movespeed_modifier(/datum/movespeed_modifier/damage_slowdown_flying)

code/modules/mob/living/carbon/monkey/monkey.dm

@@ -74,9 +74,10 @@
 /mob/living/carbon/monkey/updatehealth()
 	. = ..()
 	var/slow = 0
-	var/health_deficiency = (100 - health)
+	if(!HAS_TRAIT(src, TRAIT_IGNOREDAMAGESLOWDOWN))
-	if(health_deficiency >= 45)
+		var/health_deficiency = (maxHealth - health)
-		slow += (health_deficiency / 25)
+		if(health_deficiency >= 45)
+			slow += (health_deficiency / 25)
 	add_or_update_variable_movespeed_modifier(/datum/movespeed_modifier/monkey_health_speedmod, TRUE, slow)
 
 /mob/living/carbon/monkey/adjust_bodytemperature(amount)

code/modules/mob/living/living.dm

@@ -502,8 +502,16 @@
 				var/obj/effect/proc_holder/spell/spell = S
 				spell.updateButtonIcon()
 
+//proc used to remove all immobilisation effects + reset stamina
+/mob/living/proc/remove_CC(should_update_mobility = TRUE)
+	SetAllImmobility(0, FALSE)
+	setStaminaLoss(0)
+	SetUnconscious(0, FALSE)
+	if(should_update_mobility)
+		update_mobility()
+
 //proc used to completely heal a mob.
-/mob/living/proc/fully_heal(admin_revive = 0)
+/mob/living/proc/fully_heal(admin_revive = FALSE)
 	restore_blood()
 	setToxLoss(0, 0) //zero as second argument not automatically call updatehealth().
 	setOxyLoss(0, 0)

code/modules/mob/living/simple_animal/slime/slime.dm

@@ -159,12 +159,13 @@
 /mob/living/simple_animal/slime/updatehealth()
 	. = ..()
 	remove_movespeed_modifier(/datum/movespeed_modifier/slime_healthmod)
-	var/health_deficiency = (100 - health)
 	var/mod = 0
-	if(health_deficiency >= 45)
+	if(!HAS_TRAIT(src, TRAIT_IGNOREDAMAGESLOWDOWN))
-		mod += (health_deficiency / 25)
+		var/health_deficiency = (maxHealth - health)
-	if(health <= 0)
+		if(health_deficiency >= 45)
-		mod += 2
+			mod += (health_deficiency / 25)
+		if(health <= 0)
+			mod += 2
 	add_or_update_variable_movespeed_modifier(/datum/movespeed_modifier/slime_healthmod, multiplicative_slowdown = mod)
 
 /mob/living/simple_animal/slime/adjust_bodytemperature()