diff --git a/code/controllers/subsystems/icon_cache.dm b/code/controllers/subsystems/icon_cache.dm
index dc9956e7338..ce178b8b25b 100644
--- a/code/controllers/subsystems/icon_cache.dm
+++ b/code/controllers/subsystems/icon_cache.dm
@@ -50,9 +50,6 @@
 	//    haironly:   nobeard_[hair_style][r_hair][g_hair][b_hair]
 	//    beardonly:  [beard_style][r_facial][g_facial][b_facial]_nohair
 	var/list/human_hair_cache = list()
-	var/list/human_underwear_cache = list()
-	var/list/human_undershirt_cache = list()
-	var/list/human_socks_cache = list()
 	var/list/organ_keymap = list()
 	var/current_organ_keymap_idex = 1
 	// This is an assoc list of all icon states in `icons/mob/collar.dmi`, used by human update-icons.
@@ -73,6 +70,8 @@
 	var/list/space_cache = list()
 	var/list/crayon_cache = list()
 
+	var/list/istate_cache = list()
+
 /datum/controller/subsystem/icon_cache/New()
 	NEW_SS_GLOBAL(SSicon_cache)
 
@@ -95,7 +94,7 @@
 	var/key = organ.get_mob_cache_key(FALSE)
 	. = organ_keymap[key]
 	if (!.)
-		organ_keymap[key] = "organ[current_organ_keymap_idex++]"
+		organ_keymap[key] = "o[current_organ_keymap_idex++]"
 		. = organ_keymap[key]
 
 /datum/controller/subsystem/icon_cache/proc/setup_uniform_mappings()
@@ -124,3 +123,35 @@
 		I.icon_state = istr
 		I.overlays += space_dust_cache[istr]
 		space_cache[istr] = I
+
+/datum/controller/subsystem/icon_cache/proc/get_state(icon/I, state)	// returns an APPEARANCE, not an image!
+	if (!isicon(I))
+		CRASH("Expected icon.")
+
+	if (!istext(state))
+		// non-fatal, so just print a message then carry on.
+		crash_with("Received non-text icon_state '[state || "(NULL)"]'; normalizing, but this shouldn't happen.")
+		state = "[state]"
+
+	var/list/cache = istate_cache[I]
+	if (cache)
+		if (cache[state])
+			return cache[state]
+	else
+		cache = preload_icon(I)
+
+	var/image/im = image(icon = I, icon_state = state)
+	return cache[state] = im.appearance
+
+// Loads all icon states in an icon into the istate cache.
+/datum/controller/subsystem/icon_cache/proc/preload_icon(icon/I)
+	log_debug("SSicon_cache: preloading '[I]'...")
+	var/list/cache = list()
+	var/image/im = new(icon = I)
+	for (var/state in icon_states(I))
+		im.icon_state = state
+		cache[state] = im.appearance
+
+	log_debug("SSicon_cache: preloaded [cache.len] states.")
+	istate_cache[I] = cache
+	return cache
diff --git a/code/game/gamemodes/cult/runes.dm b/code/game/gamemodes/cult/runes.dm
index 713ce496dbf..5e20a6b052b 100644
--- a/code/game/gamemodes/cult/runes.dm
+++ b/code/game/gamemodes/cult/runes.dm
@@ -448,7 +448,7 @@ var/list/sacrificed = list()
 			chose_name = 1
 			break
 	D.universal_speak = 1
-	D.underwear = 0
+	D.underwear = null
 	D.key = ghost.key
 	cult.add_antagonist(D.mind)
 	playsound(loc, 'sound/magic/exit_blood.ogg', 100, 1)
diff --git a/code/game/objects/structures/under_wardrobe.dm b/code/game/objects/structures/under_wardrobe.dm
index 639887a6030..0e4b1ca6520 100644
--- a/code/game/objects/structures/under_wardrobe.dm
+++ b/code/game/objects/structures/under_wardrobe.dm
@@ -54,7 +54,7 @@
 			if(F_UNDER)
 				H.underwear = selection[pick]
 
-		H.update_body(1)
+		H.update_underwear(TRUE)
 
 	return 1
 
diff --git a/code/game/turfs/turf.dm b/code/game/turfs/turf.dm
index 8ea21884ad9..ffbdbba0e2d 100644
--- a/code/game/turfs/turf.dm
+++ b/code/game/turfs/turf.dm
@@ -176,20 +176,16 @@
 	return 1 //Nothing found to block so return success!
 
 var/const/enterloopsanity = 100
-/turf/Entered(atom/atom as mob|obj)
 
+/turf/Entered(atom/movable/AM)
 	if(movement_disabled)
 		usr << "<span class='warning'>Movement is admin-disabled.</span>" //This is to identify lag problems
 		return
-	..()
 
-	if(!istype(atom, /atom/movable))
-		return
+	ASSERT(istype(AM))
 
-	var/atom/movable/A = atom
-
-	if(ismob(A))
-		var/mob/M = A
+	if(ismob(AM))
+		var/mob/M = AM
 		if(!M.lastarea)
 			M.lastarea = get_area(M.loc)
 		if(M.lastarea.has_gravity() == 0)
@@ -197,21 +193,26 @@ var/const/enterloopsanity = 100
 
 		// Footstep SFX logic moved to human_movement.dm - Move().
 
-		else if(!istype(src, /turf/space))
+		else if (type != /turf/space)
 			M.inertia_dir = 0
 			M.make_floating(0)
+
 	..()
+
 	var/objects = 0
-	if(A && (A.flags & PROXMOVE) && A.simulated)
-		for(var/atom/movable/thing in range(1))
-			if(objects > enterloopsanity) break
+	if(AM && (AM.flags & PROXMOVE) && AM.simulated)
+		for(var/atom/movable/oAM in range(1))
+			if(objects > enterloopsanity)
+				break
 			objects++
-			spawn(0)
-				if(A)
-					A.HasProximity(thing, 1)
-					if ((thing && A) && (thing.flags & PROXMOVE))
-						thing.HasProximity(A, 1)
-	return
+
+			if (oAM.simulated)
+				addtimer(CALLBACK(AM, /atom/movable/.proc/proximity_callback, oAM), 0)
+
+/atom/movable/proc/proximity_callback(atom/movable/AM)
+	HasProximity(AM, TRUE)
+	if (!QDELETED(AM) && !QDELETED(src) && (AM.flags & PROXMOVE))
+		AM.HasProximity(src, TRUE)
 
 /turf/proc/adjacent_fire_act(turf/simulated/floor/source, temperature, volume)
 	return
diff --git a/code/modules/client/preferences.dm b/code/modules/client/preferences.dm
index aa9b19c2fd7..282bc34eb0c 100644
--- a/code/modules/client/preferences.dm
+++ b/code/modules/client/preferences.dm
@@ -387,6 +387,7 @@ datum/preferences
 		character.update_mutations(0)
 		character.update_body(0)
 		character.update_hair(0)
+		character.update_underwear(0)
 		character.update_icons()
 
 /datum/preferences/proc/open_load_dialog_sql(mob/user)
diff --git a/code/modules/mob/living/carbon/human/update_icons.dm b/code/modules/mob/living/carbon/human/update_icons.dm
index f64a75582bc..02f6c5f243e 100644
--- a/code/modules/mob/living/carbon/human/update_icons.dm
+++ b/code/modules/mob/living/carbon/human/update_icons.dm
@@ -87,28 +87,29 @@ There are several things that need to be remembered:
 #define MUTATIONS_LAYER   1
 #define DAMAGE_LAYER      2
 #define SURGERY_LAYER     3
-#define UNIFORM_LAYER     4
-#define ID_LAYER          5
-#define SHOES_LAYER       6
-#define GLOVES_LAYER      7
-#define BELT_LAYER        8
-#define SUIT_LAYER        9
-#define TAIL_LAYER       10
-#define GLASSES_LAYER    11
-#define BELT_LAYER_ALT   12
-#define SUIT_STORE_LAYER 13
-#define BACK_LAYER       14
-#define HAIR_LAYER       15
-#define EARS_LAYER       16
-#define FACEMASK_LAYER   17
-#define HEAD_LAYER       18
-#define COLLAR_LAYER     19
-#define HANDCUFF_LAYER   20
-#define LEGCUFF_LAYER    21
-#define L_HAND_LAYER     22
-#define R_HAND_LAYER     23
-#define FIRE_LAYER       24		//If you're on fire
-#define TOTAL_LAYERS     24
+#define UNDERWEAR_LAYER   4
+#define UNIFORM_LAYER     5
+#define ID_LAYER          6
+#define SHOES_LAYER       7
+#define GLOVES_LAYER      8
+#define BELT_LAYER        9
+#define SUIT_LAYER       10
+#define TAIL_LAYER       11
+#define GLASSES_LAYER    12
+#define BELT_LAYER_ALT   13
+#define SUIT_STORE_LAYER 14
+#define BACK_LAYER       15
+#define HAIR_LAYER       16
+#define EARS_LAYER       17
+#define FACEMASK_LAYER   18
+#define HEAD_LAYER       19
+#define COLLAR_LAYER     20
+#define HANDCUFF_LAYER   21
+#define LEGCUFF_LAYER    22
+#define L_HAND_LAYER     23
+#define R_HAND_LAYER     24
+#define FIRE_LAYER       25		//If you're on fire
+#define TOTAL_LAYERS     25
 //////////////////////////////////
 
 #define UNDERSCORE_OR_NULL(target) "[target ? "[target]_" : ""]"
@@ -261,17 +262,17 @@ There are several things that need to be remembered:
 			//And no change in rendering for other parts (they icon_position is 0, so goes to 'else' part)
 			if(part.icon_position&(LEFT|RIGHT))
 				var/icon/temp2 = new('icons/mob/human.dmi',"blank")
-				temp2.Insert(new/icon(temp,dir=NORTH),dir=NORTH)
-				temp2.Insert(new/icon(temp,dir=SOUTH),dir=SOUTH)
+				temp2.Insert(new /icon(temp ,dir = NORTH), dir = NORTH)
+				temp2.Insert(new /icon(temp, dir = SOUTH), dir = SOUTH)
 				if(!(part.icon_position & LEFT))
-					temp2.Insert(new/icon(temp,dir=EAST),dir=EAST)
+					temp2.Insert(new /icon(temp, dir = EAST), dir = EAST)
 				if(!(part.icon_position & RIGHT))
-					temp2.Insert(new/icon(temp,dir=WEST),dir=WEST)
+					temp2.Insert(new /icon(temp, dir = WEST), dir = WEST)
 				base_icon.Blend(temp2, ICON_OVERLAY)
 				if(part.icon_position & LEFT)
-					temp2.Insert(new/icon(temp,dir=EAST),dir=EAST)
+					temp2.Insert(new /icon(temp, dir = EAST), dir = EAST)
 				if(part.icon_position & RIGHT)
-					temp2.Insert(new/icon(temp,dir=WEST),dir=WEST)
+					temp2.Insert(new /icon(temp, dir = WEST), dir = WEST)
 				base_icon.Blend(temp2, ICON_UNDERLAY)
 			else
 				base_icon.Blend(temp, ICON_OVERLAY)
@@ -296,37 +297,29 @@ There are several things that need to be remembered:
 	//END CACHED ICON GENERATION.
 	stand_icon.Blend(base_icon,ICON_OVERLAY)
 
-	//Underwear
-	if(underwear && species.appearance_flags & HAS_UNDERWEAR)
-		var/uwear = "[underwear]"
-		var/icon/undies = SSicon_cache.human_underwear_cache[uwear]
-		if (!undies)
-			undies = new('icons/mob/human.dmi', underwear)
-			SSicon_cache.human_underwear_cache[uwear] = undies
-		stand_icon.Blend(undies, ICON_OVERLAY)
-
-	if(undershirt && species.appearance_flags & HAS_UNDERWEAR)
-		var/ushirt = "[undershirt]"
-		var/icon/shirt = SSicon_cache.human_undershirt_cache[ushirt]
-		if (!shirt)
-			shirt = new('icons/mob/human.dmi', undershirt)
-			SSicon_cache.human_undershirt_cache[ushirt] = shirt
-		stand_icon.Blend(shirt, ICON_OVERLAY)
-
-	if(socks && species.appearance_flags & HAS_SOCKS)
-		var/sockskey = "[socks]"
-		var/icon/socksicon = SSicon_cache.human_socks_cache[sockskey]
-		if (!socksicon)
-			socksicon = new('icons/mob/human.dmi', socks)
-			SSicon_cache.human_socks_cache[sockskey] = socksicon
-		stand_icon.Blend(socksicon, ICON_OVERLAY)
-
 	if(update_icons)
 		update_icons()
 
 	//tail
 	update_tail_showing(0)
 
+/mob/living/carbon/human/proc/update_underwear(update_icons = TRUE)
+	var/list/ovr
+
+	if(underwear && (species.appearance_flags & HAS_UNDERWEAR))
+		LAZYADD(ovr, SSicon_cache.get_state('icons/mob/human.dmi', "[underwear]"))
+
+	if(undershirt && (species.appearance_flags & HAS_UNDERWEAR))
+		LAZYADD(ovr, SSicon_cache.get_state('icons/mob/human.dmi', "[undershirt]"))
+
+	if(socks && (species.appearance_flags & HAS_SOCKS))
+		LAZYADD(ovr, SSicon_cache.get_state('icons/mob/human.dmi', "[socks]"))
+
+	overlays_raw[UNDERWEAR_LAYER] = ovr
+
+	if (update_icons)
+		update_icons()
+
 // This proc generates & returns an icon representing a human's hair, using a cached icon from SSicon_cache if possible.
 // If `hair_is_visible` is FALSE, only facial hair will be drawn.
 /mob/living/carbon/human/proc/generate_hair_icon(hair_is_visible = TRUE)
@@ -451,30 +444,33 @@ There are several things that need to be remembered:
 		return
 
 	..()
-	if(transforming)		return
 
-	update_mutations(0)
-	update_body(0)
-	update_hair(0)
-	update_inv_w_uniform(0)
-	update_inv_wear_id(0)
-	update_inv_gloves(0)
-	update_inv_glasses(0)
-	update_inv_ears(0)
-	update_inv_shoes(0)
-	update_inv_s_store(0)
-	update_inv_wear_mask(0)
-	update_inv_head(0)
-	update_inv_belt(0)
-	update_inv_back(0)
-	update_inv_wear_suit(0)
-	update_inv_r_hand(0)
-	update_inv_l_hand(0)
-	update_inv_handcuffed(0)
-	update_inv_legcuffed(0)
-	update_inv_pockets(0)
-	update_fire(0)
-	update_surgery(0)
+	if(transforming)
+		return
+
+	update_mutations(FALSE)
+	update_body(FALSE)
+	update_hair(FALSE)
+	update_inv_w_uniform(FALSE)
+	update_inv_wear_id(FALSE)
+	update_inv_gloves(FALSE)
+	update_inv_glasses(FALSE)
+	update_inv_ears(FALSE)
+	update_inv_shoes(FALSE)
+	update_inv_s_store(FALSE)
+	update_inv_wear_mask(FALSE)
+	update_inv_head(FALSE)
+	update_inv_belt(FALSE)
+	update_inv_back(FALSE)
+	update_inv_wear_suit(FALSE)
+	update_inv_r_hand(FALSE)
+	update_inv_l_hand(FALSE)
+	update_inv_handcuffed(FALSE)
+	update_inv_legcuffed(FALSE)
+	update_inv_pockets(FALSE)
+	update_fire(FALSE)
+	update_surgery(FALSE)
+	update_underwear(FALSE)
 	UpdateDamageIcon()
 	update_icons()
 	//Hud Stuff
diff --git a/code/modules/multiz/zmimic/mimic_turf.dm b/code/modules/multiz/zmimic/mimic_turf.dm
index d89350e4b3f..ac079a718e6 100644
--- a/code/modules/multiz/zmimic/mimic_turf.dm
+++ b/code/modules/multiz/zmimic/mimic_turf.dm
@@ -7,7 +7,7 @@
 
 /turf/Entered(atom/movable/thing, turf/oldLoc)
 	. = ..()
-	if (thing.bound_overlay || !thing.no_z_overlay || !above || !(above.flags & MIMIC_BELOW) || (isturf(oldLoc) && oldLoc.above && (oldLoc.above.flags & MIMIC_BELOW)))
+	if (thing.bound_overlay || thing.no_z_overlay || !TURF_IS_MIMICING(above))
 		return
 	above.update_mimic()
 
diff --git a/html/changelogs/lohikar-aaaa.yml b/html/changelogs/lohikar-aaaa.yml
new file mode 100644
index 00000000000..a7f0c6ac931
--- /dev/null
+++ b/html/changelogs/lohikar-aaaa.yml
@@ -0,0 +1,4 @@
+author: Lohikar
+delete-after: True
+changes: 
+  - bugfix: "Openspaces will now properly show mobs/objects that became visible after roundstart."