diff --git a/code/__DEFINES/traits.dm b/code/__DEFINES/traits.dm
index 7ef7a0f10c38..b30b96f0662a 100644
--- a/code/__DEFINES/traits.dm
+++ b/code/__DEFINES/traits.dm
@@ -144,6 +144,10 @@ Remember to update _globalvars/traits.dm if you're adding/removing/renaming trai
 #define TRAIT_PULL_BLOCKED "pullblocked"
 /// Abstract condition that prevents movement if being pulled and might be resisted against. Handcuffs and straight jackets, basically.
 #define TRAIT_RESTRAINED "restrained"
+/// Apply this to make a mob not dense, and remove it when you want it to no longer make them undense, other sorces of undesity will still apply. Always define a unique source when adding a new instance of this!
+#define TRAIT_UNDENSE "undense"
+/// Expands our FOV by 30 degrees if restricted
+#define TRAIT_EXPANDED_FOV "expanded_fov"
 /// Doesn't miss attacks
 #define TRAIT_PERFECT_ATTACKER "perfect_attacker"
 #define TRAIT_INCAPACITATED "incapacitated"
@@ -899,6 +903,8 @@ Remember to update _globalvars/traits.dm if you're adding/removing/renaming trai
 #define SUIT_TRAIT "suit"
 /// Trait associated to lying down (having a [lying_angle] of a different value than zero).
 #define LYING_DOWN_TRAIT "lying-down"
+/// A trait gained by leaning against a wall
+#define LEANING_TRAIT "leaning"
 /// Trait associated to lacking electrical power.
 #define POWER_LACK_TRAIT "power-lack"
 /// Trait associated to lacking motor movement
@@ -968,7 +974,15 @@ Remember to update _globalvars/traits.dm if you're adding/removing/renaming trai
 #define SPECIES_FLIGHT_TRAIT "species-flight"
 #define FROSTMINER_ENRAGE_TRAIT "frostminer-enrage"
 #define NO_GRAVITY_TRAIT "no-gravity"
+/// A trait gained from a mob's leap action, like the leaper
 #define LEAPING_TRAIT "leaping"
+/// A trait gained from a mob's vanish action, like the herophant
+#define VANISHING_TRAIT "vanishing"
+/// A trait gained from a mob's swoop action, like the ash drake
+#define SWOOPING_TRAIT "swooping"
+/// A trait gained from a mob's mimic ability, like the mimic
+#define MIMIC_TRAIT "mimic"
+#define SHRUNKEN_TRAIT "shrunken"
 #define LEAPER_BUBBLE_TRAIT "leaper-bubble"
 #define DNA_VAULT_TRAIT "dna_vault"
 /// sticky nodrop sounds like a bad soundcloud rapper's name
diff --git a/code/_globalvars/traits.dm b/code/_globalvars/traits.dm
index 55326d5633ef..fce0b00572d0 100644
--- a/code/_globalvars/traits.dm
+++ b/code/_globalvars/traits.dm
@@ -192,6 +192,8 @@ GLOBAL_LIST_INIT(traits_by_type, list(
 		"TRAIT_MIMING" = TRAIT_MIMING,
 		"TRAIT_PREVENT_IMPLANT_AUTO_EXPLOSION" = TRAIT_PREVENT_IMPLANT_AUTO_EXPLOSION,
 		"TRAIT_UNOBSERVANT" = TRAIT_UNOBSERVANT,
+		"TRAIT_UNDENSE" = TRAIT_UNDENSE,
+		"TRAIT_EXPANDED_FOV" = TRAIT_EXPANDED_FOV,
 		"TRAIT_TENTACLE_IMMUNE" = TRAIT_TENTACLE_IMMUNE,
 		"TRAIT_OVERWATCH_IMMUNE" = TRAIT_OVERWATCH_IMMUNE,
 	),
diff --git a/code/datums/actions/mobs/lava_swoop.dm b/code/datums/actions/mobs/lava_swoop.dm
index d23252c73aac..d18ad2f3af3b 100644
--- a/code/datums/actions/mobs/lava_swoop.dm
+++ b/code/datums/actions/mobs/lava_swoop.dm
@@ -38,7 +38,7 @@
 		return
 	// stop swooped target movement
 	swooping = TRUE
-	owner.set_density(FALSE)
+	ADD_TRAIT(owner, TRAIT_UNDENSE, SWOOPING_TRAIT)
 	owner.visible_message(span_boldwarning("[owner] swoops up high!"))
 
 	var/negative
@@ -115,7 +115,7 @@
 	for(var/mob/M in range(7, owner))
 		shake_camera(M, 15, 1)
 
-	owner.set_density(TRUE)
+	REMOVE_TRAIT(owner, TRAIT_UNDENSE, SWOOPING_TRAIT)
 	SLEEP_CHECK_DEATH(1, owner)
 	swooping = FALSE
 	if(!lava_success)
diff --git a/code/datums/components/riding/riding_mob.dm b/code/datums/components/riding/riding_mob.dm
index 5a829df75f81..7c182d621183 100644
--- a/code/datums/components/riding/riding_mob.dm
+++ b/code/datums/components/riding/riding_mob.dm
@@ -203,7 +203,7 @@
 		human_parent.buckle_lying = 0
 		// the riding mob is made nondense so they don't bump into any dense atoms the carrier is pulling,
 		// since pulled movables are moved before buckled movables
-		riding_mob.set_density(FALSE)
+		ADD_TRAIT(riding_mob, TRAIT_UNDENSE, VEHICLE_TRAIT)
 	else if(ride_check_flags & CARRIER_NEEDS_ARM) // fireman
 		human_parent.buckle_lying = 90
 
@@ -227,7 +227,7 @@
 	unequip_buckle_inhands(parent)
 	var/mob/living/carbon/human/H = parent
 	H.remove_movespeed_modifier(/datum/movespeed_modifier/human_carry)
-	former_rider.set_density(!former_rider.body_position)
+	REMOVE_TRAIT(H, TRAIT_UNDENSE, VEHICLE_TRAIT)
 	return ..()
 
 /// If the carrier shoves the person they're carrying, force the carried mob off
diff --git a/code/datums/components/shrink.dm b/code/datums/components/shrink.dm
index 9c1c5f76dcde..67cd3d39e23c 100644
--- a/code/datums/components/shrink.dm
+++ b/code/datums/components/shrink.dm
@@ -10,10 +10,11 @@
 	parent_atom.transform = parent_atom.transform.Scale(0.5,0.5)
 	olddens = parent_atom.density
 	oldopac = parent_atom.opacity
-	parent_atom.set_density(FALSE)
+
 	parent_atom.set_opacity(FALSE)
 	if(isliving(parent_atom))
 		var/mob/living/L = parent_atom
+		ADD_TRAIT(L, TRAIT_UNDENSE, SHRUNKEN_TRAIT)
 		L.add_movespeed_modifier(/datum/movespeed_modifier/shrink_ray)
 		if(iscarbon(L))
 			var/mob/living/carbon/C = L
@@ -23,6 +24,8 @@
 			if(ishuman(C))
 				var/mob/living/carbon/human/H = C
 				H.physiology.damage_resistance -= 100//carbons take double damage while shrunk
+	else
+		parent_atom.set_density(FALSE) // this is handled by the UNDENSE trait on mobs
 	parent_atom.visible_message(span_warning("[parent_atom] shrinks down to a tiny size!"),
 	span_userdanger("Everything grows bigger!"))
 	QDEL_IN(src, shrink_time)
@@ -30,12 +33,14 @@
 /datum/component/shrink/Destroy()
 	var/atom/parent_atom = parent
 	parent_atom.transform = parent_atom.transform.Scale(2,2)
-	parent_atom.set_density(olddens)
 	parent_atom.set_opacity(oldopac)
 	if(isliving(parent_atom))
 		var/mob/living/L = parent_atom
 		L.remove_movespeed_modifier(/datum/movespeed_modifier/shrink_ray)
+		REMOVE_TRAIT(L, TRAIT_UNDENSE, SHRUNKEN_TRAIT)
 		if(ishuman(L))
 			var/mob/living/carbon/human/H = L
 			H.physiology.damage_resistance += 100
+	else
+		parent_atom.set_density(olddens) // this is handled by the UNDENSE trait on mobs
 	return ..()
diff --git a/code/game/objects/items.dm b/code/game/objects/items.dm
index e3af3614fa1c..84e64497afb5 100644
--- a/code/game/objects/items.dm
+++ b/code/game/objects/items.dm
@@ -212,6 +212,8 @@
 	var/offensive_notes
 	/// Used in obj/item/examine to determines whether or not to detail an item's statistics even if it does not meet the force requirements
 	var/override_notes = FALSE
+	/// Used if we want to have a custom verb text for throwing. "John Spaceman flicks the ciggerate" for example.
+	var/throw_verb
 
 /obj/item/Initialize(mapload)
 
diff --git a/code/game/objects/items/cigs_lighters.dm b/code/game/objects/items/cigs_lighters.dm
index eb9444784e21..4fc8935b3d49 100644
--- a/code/game/objects/items/cigs_lighters.dm
+++ b/code/game/objects/items/cigs_lighters.dm
@@ -138,6 +138,7 @@ CIGARETTE PACKETS ARE IN FANCY.DM
 	body_parts_covered = null
 	grind_results = list()
 	heat = 1000
+	throw_verb = "flick"
 	/// Whether this cigarette has been lit.
 	var/lit = FALSE
 	/// Whether this cigarette should start lit.
diff --git a/code/game/turfs/closed/walls.dm b/code/game/turfs/closed/walls.dm
index 4d7595b91895..acac18383a91 100644
--- a/code/game/turfs/closed/walls.dm
+++ b/code/game/turfs/closed/walls.dm
@@ -1,4 +1,5 @@
 #define MAX_DENT_DECALS 15
+#define LEANING_OFFSET 11
 
 /turf/closed/wall
 	name = "wall"
@@ -33,6 +34,50 @@
 
 	var/list/dent_decals
 
+/turf/closed/wall/MouseDrop_T(mob/living/carbon/carbon_mob, mob/user)
+	..()
+	if(carbon_mob != user)
+		return
+	if(carbon_mob.is_leaning == TRUE)
+		return
+	if(carbon_mob.pulledby)
+		return
+	if(!carbon_mob.density)
+		return
+	carbon_mob.is_leaning = TRUE
+	var/turf/checked_turf = get_step(carbon_mob, turn(carbon_mob.dir, 180))
+	if(checked_turf == src)
+		carbon_mob.start_leaning(src)
+
+/mob/living/carbon/proc/start_leaning(obj/wall)
+
+	switch(dir)
+		if(SOUTH)
+			pixel_y += LEANING_OFFSET
+		if(NORTH)
+			pixel_y += -LEANING_OFFSET
+		if(WEST)
+			pixel_x += LEANING_OFFSET
+		if(EAST)
+			pixel_x += -LEANING_OFFSET
+
+	ADD_TRAIT(src, TRAIT_UNDENSE, LEANING_TRAIT)
+	ADD_TRAIT(src, TRAIT_EXPANDED_FOV, LEANING_TRAIT)
+	visible_message(span_notice("[src] leans against \the [wall]!"), \
+						span_notice("You lean against \the [wall]!"))
+	RegisterSignals(src, list(COMSIG_MOB_CLIENT_PRE_MOVE, COMSIG_HUMAN_DISARM_HIT, COMSIG_LIVING_GET_PULLED, COMSIG_MOVABLE_TELEPORTING, COMSIG_ATOM_DIR_CHANGE), PROC_REF(stop_leaning))
+	update_fov()
+
+/mob/living/carbon/proc/stop_leaning()
+	SIGNAL_HANDLER
+	UnregisterSignal(src, list(COMSIG_MOB_CLIENT_PRE_MOVE, COMSIG_HUMAN_DISARM_HIT, COMSIG_LIVING_GET_PULLED, COMSIG_MOVABLE_TELEPORTING, COMSIG_ATOM_DIR_CHANGE))
+	is_leaning = FALSE
+	pixel_y = base_pixel_y + body_position_pixel_x_offset
+	pixel_x = base_pixel_y + body_position_pixel_y_offset
+	REMOVE_TRAIT(src, TRAIT_UNDENSE, LEANING_TRAIT)
+	REMOVE_TRAIT(src, TRAIT_EXPANDED_FOV, LEANING_TRAIT)
+	update_fov()
+
 /turf/closed/wall/Initialize(mapload)
 	. = ..()
 	if(!can_engrave)
@@ -329,3 +374,4 @@
 	girder_type = /obj/structure/foamedmetal
 
 #undef MAX_DENT_DECALS
+#undef LEANING_OFFSET
diff --git a/code/modules/mob/living/basic/basic.dm b/code/modules/mob/living/basic/basic.dm
index 14ff9c0e5f38..4ba206bd46fa 100644
--- a/code/modules/mob/living/basic/basic.dm
+++ b/code/modules/mob/living/basic/basic.dm
@@ -152,7 +152,7 @@
 	if(basic_mob_flags & FLIP_ON_DEATH)
 		transform = transform.Turn(180)
 	if(!(basic_mob_flags & REMAIN_DENSE_WHILE_DEAD))
-		set_density(FALSE)
+		ADD_TRAIT(src, TRAIT_UNDENSE, BASIC_MOB_DEATH_TRAIT)
 	SEND_SIGNAL(src, COMSIG_BASICMOB_LOOK_DEAD)
 
 /mob/living/basic/revive(full_heal_flags = NONE, excess_healing = 0, force_grab_ghost = FALSE)
@@ -167,7 +167,7 @@
 	if(basic_mob_flags & FLIP_ON_DEATH)
 		transform = transform.Turn(180)
 	if(!(basic_mob_flags & REMAIN_DENSE_WHILE_DEAD))
-		set_density(FALSE)
+		REMOVE_TRAIT(src, TRAIT_UNDENSE, BASIC_MOB_DEATH_TRAIT)
 	SEND_SIGNAL(src, COMSIG_BASICMOB_LOOK_ALIVE)
 
 /mob/living/basic/update_sight()
diff --git a/code/modules/mob/living/carbon/carbon.dm b/code/modules/mob/living/carbon/carbon.dm
index 337c7e0d7e10..fa850f0a3a8a 100644
--- a/code/modules/mob/living/carbon/carbon.dm
+++ b/code/modules/mob/living/carbon/carbon.dm
@@ -164,6 +164,9 @@
 		return FALSE
 	var/atom/movable/thrown_thing
 	var/obj/item/held_item = get_active_held_item()
+	var/verb_text = pick("throw", "toss", "hurl", "chuck", "fling")
+	if(prob(0.5))
+		verb_text = "yeet"
 	var/neckgrab_throw = FALSE // we can't check for if it's a neckgrab throw when totaling up power_throw since we've already stopped pulling them by then, so get it early
 	if(!held_item)
 		if(pulling && isliving(pulling) && grab_state >= GRAB_AGGRESSIVE)
@@ -194,8 +197,12 @@
 		power_throw++
 	if(neckgrab_throw)
 		power_throw++
-	visible_message(span_danger("[src] throws [thrown_thing][power_throw ? " really hard!" : "."]"), \
-					span_danger("You throw [thrown_thing][power_throw ? " really hard!" : "."]"))
+	if(isitem(thrown_thing))
+		var/obj/item/thrown_item = thrown_thing
+		if(thrown_item.throw_verb)
+			verb_text = thrown_item.throw_verb
+	visible_message(span_danger("[src] [plural_s(verb_text)] [thrown_thing][power_throw ? " really hard!" : "."]"), \
+					span_danger("You [verb_text] [thrown_thing][power_throw ? " really hard!" : "."]"))
 	log_message("has thrown [thrown_thing] [power_throw > 0 ? "really hard" : ""]", LOG_ATTACK)
 	var/extra_throw_range = HAS_TRAIT(src, TRAIT_THROWINGARM) ? 2 : 0
 	newtonian_move(get_dir(target, src))
diff --git a/code/modules/mob/living/carbon/carbon_defines.dm b/code/modules/mob/living/carbon/carbon_defines.dm
index f5cee1ec422c..11c8a62b69b4 100644
--- a/code/modules/mob/living/carbon/carbon_defines.dm
+++ b/code/modules/mob/living/carbon/carbon_defines.dm
@@ -113,6 +113,8 @@
 	/// Stores the result of our last known top_offset generation for optimisation purposes when drawing limb icons.
 	var/last_top_offset
 
+	var/is_leaning = FALSE
+
 	COOLDOWN_DECLARE(bleeding_message_cd)
 
 	var/next_smell = 0 /// Cooldown for the next smell
diff --git a/code/modules/mob/living/init_signals.dm b/code/modules/mob/living/init_signals.dm
index 6c4d59f93df1..fae78c27fc86 100644
--- a/code/modules/mob/living/init_signals.dm
+++ b/code/modules/mob/living/init_signals.dm
@@ -44,6 +44,7 @@
 	RegisterSignal(src, SIGNAL_ADDTRAIT(TRAIT_SKITTISH), PROC_REF(on_skittish_trait_gain))
 	RegisterSignal(src, SIGNAL_REMOVETRAIT(TRAIT_SKITTISH), PROC_REF(on_skittish_trait_loss))
 
+	RegisterSignals(src, list(SIGNAL_ADDTRAIT(TRAIT_UNDENSE), SIGNAL_REMOVETRAIT(TRAIT_UNDENSE)), PROC_REF(undense_changed))
 	RegisterSignals(src, list(SIGNAL_ADDTRAIT(TRAIT_NEGATES_GRAVITY), SIGNAL_REMOVETRAIT(TRAIT_NEGATES_GRAVITY)), PROC_REF(on_negate_gravity))
 	RegisterSignals(src, list(SIGNAL_ADDTRAIT(TRAIT_IGNORING_GRAVITY), SIGNAL_REMOVETRAIT(TRAIT_IGNORING_GRAVITY)), PROC_REF(on_ignore_gravity))
 	RegisterSignals(src, list(SIGNAL_ADDTRAIT(TRAIT_FORCED_GRAVITY), SIGNAL_REMOVETRAIT(TRAIT_FORCED_GRAVITY)), PROC_REF(on_force_gravity))
@@ -245,3 +246,8 @@
 /mob/living/proc/on_loc_force_gravity(datum/source)
 	SIGNAL_HANDLER
 	refresh_gravity()
+
+/// Called when [TRAIT_UNDENSE] is gained or lost
+/mob/living/proc/undense_changed(datum/source)
+	SIGNAL_HANDLER
+	update_density()
diff --git a/code/modules/mob/living/living.dm b/code/modules/mob/living/living.dm
index 34155f199a1f..52fd43f9b2e8 100644
--- a/code/modules/mob/living/living.dm
+++ b/code/modules/mob/living/living.dm
@@ -660,8 +660,7 @@
 /mob/living/proc/on_lying_down(new_lying_angle)
 	if(layer == initial(layer)) //to avoid things like hiding larvas.
 		layer = LYING_MOB_LAYER //so mob lying always appear behind standing mobs
-	add_traits(list(TRAIT_UI_BLOCKED, TRAIT_PULL_BLOCKED), LYING_DOWN_TRAIT)
-	set_density(FALSE) // We lose density and stop bumping passable dense things.
+	add_traits(list(TRAIT_UI_BLOCKED, TRAIT_PULL_BLOCKED, TRAIT_UNDENSE), LYING_DOWN_TRAIT)
 	if(HAS_TRAIT(src, TRAIT_FLOORED) && !(dir & (NORTH|SOUTH)))
 		setDir(pick(NORTH, SOUTH)) // We are and look helpless.
 	body_position_pixel_y_offset = PIXEL_Y_OFFSET_LYING
@@ -672,9 +671,16 @@
 /mob/living/proc/on_standing_up()
 	if(layer == LYING_MOB_LAYER)
 		layer = initial(layer)
-	set_density(initial(density)) // We were prone before, so we become dense and things can bump into us again.
-	remove_traits(list(TRAIT_UI_BLOCKED, TRAIT_PULL_BLOCKED), LYING_DOWN_TRAIT)
-	body_position_pixel_y_offset = 0
+	remove_traits(list(TRAIT_UI_BLOCKED, TRAIT_PULL_BLOCKED, TRAIT_UNDENSE), LYING_DOWN_TRAIT)
+	// Make sure it doesn't go out of the southern bounds of the tile when standing.
+	body_position_pixel_y_offset = 0 // MONKEYSTATION EDIT CHANGE OLD
+//	body_position_pixel_y_offset = (current_size-1) * world.icon_size/2 MONKEYSTATION EDIT CHANGE NEW - We dont have TG's PR #75892
+
+/mob/living/proc/update_density()
+	if(HAS_TRAIT(src, TRAIT_UNDENSE))
+		set_density(FALSE)
+	else
+		set_density(TRUE)
 
 //Recursive function to find everything a mob is holding. Really shitty proc tbh.
 /mob/living/get_contents()
diff --git a/code/modules/mob/living/living_fov.dm b/code/modules/mob/living/living_fov.dm
index 0c5acb7b40e4..279e8bebe328 100644
--- a/code/modules/mob/living/living_fov.dm
+++ b/code/modules/mob/living/living_fov.dm
@@ -57,6 +57,8 @@
 		if(fov_type > highest_fov)
 			highest_fov = fov_type
 	fov_view = highest_fov
+	if(HAS_TRAIT(src, TRAIT_EXPANDED_FOV))
+		fov_view += 30
 	update_fov_client()
 
 /// Updates the FOV for the client.
diff --git a/code/modules/mob/living/simple_animal/hostile/jungle/leaper.dm b/code/modules/mob/living/simple_animal/hostile/jungle/leaper.dm
index 73b7f6aa6260..7e7e0b345109 100644
--- a/code/modules/mob/living/simple_animal/hostile/jungle/leaper.dm
+++ b/code/modules/mob/living/simple_animal/hostile/jungle/leaper.dm
@@ -215,7 +215,7 @@
 	if(z != target.z)
 		return
 	hopping = TRUE
-	set_density(FALSE)
+	ADD_TRAIT(src, TRAIT_UNDENSE, LEAPING_TRAIT)
 	pass_flags |= PASSMOB
 	notransform = TRUE
 	var/turf/new_turf = locate((target.x + rand(-3,3)),(target.y + rand(-3,3)),target.z)
@@ -228,7 +228,7 @@
 	throw_at(new_turf, max(3,get_dist(src,new_turf)), 1, src, FALSE, callback = CALLBACK(src, PROC_REF(FinishHop)))
 
 /mob/living/simple_animal/hostile/jungle/leaper/proc/FinishHop()
-	set_density(TRUE)
+	REMOVE_TRAIT(src, TRAIT_UNDENSE, LEAPING_TRAIT)
 	notransform = FALSE
 	pass_flags &= ~PASSMOB
 	hopping = FALSE
@@ -245,12 +245,12 @@
 	addtimer(CALLBACK(src, PROC_REF(BellyFlopHop), new_turf), 30)
 
 /mob/living/simple_animal/hostile/jungle/leaper/proc/BellyFlopHop(turf/T)
-	set_density(FALSE)
+	ADD_TRAIT(src, TRAIT_UNDENSE, LEAPING_TRAIT)
 	throw_at(T, get_dist(src,T),1,src, FALSE, callback = CALLBACK(src, PROC_REF(Crush)))
 
 /mob/living/simple_animal/hostile/jungle/leaper/proc/Crush()
 	hopping = FALSE
-	set_density(TRUE)
+	REMOVE_TRAIT(src, TRAIT_UNDENSE, LEAPING_TRAIT)
 	notransform = FALSE
 	playsound(src, 'sound/effects/meteorimpact.ogg', 200, TRUE)
 	for(var/mob/living/L in orange(1, src))
diff --git a/code/modules/mob/living/simple_animal/hostile/jungle/mook.dm b/code/modules/mob/living/simple_animal/hostile/jungle/mook.dm
index 2e65ba824568..444635f2dc34 100644
--- a/code/modules/mob/living/simple_animal/hostile/jungle/mook.dm
+++ b/code/modules/mob/living/simple_animal/hostile/jungle/mook.dm
@@ -107,7 +107,7 @@
 /mob/living/simple_animal/hostile/jungle/mook/proc/LeapAttack()
 	if(target && !stat && attack_state == MOOK_ATTACK_WARMUP)
 		attack_state = MOOK_ATTACK_ACTIVE
-		set_density(FALSE)
+		ADD_TRAIT(src, TRAIT_UNDENSE, LEAPING_TRAIT)
 		melee_damage_lower = 30
 		melee_damage_upper = 30
 		update_icons()
@@ -123,7 +123,7 @@
 /mob/living/simple_animal/hostile/jungle/mook/proc/AttackRecovery()
 	if(attack_state == MOOK_ATTACK_ACTIVE && !stat)
 		attack_state = MOOK_ATTACK_RECOVERY
-		set_density(TRUE)
+		REMOVE_TRAIT(src, TRAIT_UNDENSE, LEAPING_TRAIT)
 		face_atom(target)
 		if(!struck_target_leap)
 			update_icons()
@@ -156,7 +156,7 @@
 		if(CanAttack(L))
 			L.attack_animal(src)
 			struck_target_leap = TRUE
-			set_density(TRUE)
+			REMOVE_TRAIT(src, TRAIT_UNDENSE, LEAPING_TRAIT)
 			update_icons()
 	var/mook_under_us = FALSE
 	for(var/A in get_turf(src))
@@ -169,7 +169,7 @@
 			if(!struck_target_leap && CanAttack(ML))//Check if some joker is attempting to use rest to evade us
 				struck_target_leap = TRUE
 				ML.attack_animal(src)
-				set_density(TRUE)
+				REMOVE_TRAIT(src, TRAIT_UNDENSE, LEAPING_TRAIT)
 				struck_target_leap = TRUE
 				update_icons()
 				continue
diff --git a/code/modules/mob/living/simple_animal/hostile/megafauna/hierophant.dm b/code/modules/mob/living/simple_animal/hostile/megafauna/hierophant.dm
index b9be840b9ae9..d2a99e86793e 100644
--- a/code/modules/mob/living/simple_animal/hostile/megafauna/hierophant.dm
+++ b/code/modules/mob/living/simple_animal/hostile/megafauna/hierophant.dm
@@ -356,13 +356,13 @@ Difficulty: Hard
 	animate(src, alpha = 0, time = 2, easing = EASE_OUT) //fade out
 	SLEEP_CHECK_DEATH(1, src)
 	visible_message(span_hierophant_warning("[src] fades out!"))
-	set_density(FALSE)
+	ADD_TRAIT(src, TRAIT_UNDENSE, VANISHING_TRAIT)
 	SLEEP_CHECK_DEATH(2, src)
 	forceMove(T)
 	SLEEP_CHECK_DEATH(1, src)
 	animate(src, alpha = 255, time = 2, easing = EASE_IN) //fade IN
 	SLEEP_CHECK_DEATH(1, src)
-	set_density(TRUE)
+	REMOVE_TRAIT(src, TRAIT_UNDENSE, VANISHING_TRAIT)
 	visible_message(span_hierophant_warning("[src] fades in!"))
 	SLEEP_CHECK_DEATH(1, src) //at this point the blasts we made detonate
 	blinking = FALSE
diff --git a/code/modules/mob/living/simple_animal/hostile/mimic.dm b/code/modules/mob/living/simple_animal/hostile/mimic.dm
index 207ae7de7149..fcc5af943de2 100644
--- a/code/modules/mob/living/simple_animal/hostile/mimic.dm
+++ b/code/modules/mob/living/simple_animal/hostile/mimic.dm
@@ -336,14 +336,14 @@ GLOBAL_LIST_INIT(animatable_blacklist, list(/obj/structure/table, /obj/structure
 	if(locked)
 		return
 	if(!opened)
-		set_density(FALSE)
+		ADD_TRAIT(src, TRAIT_UNDENSE, MIMIC_TRAIT)
 		opened = TRUE
 		icon_state = "crateopen"
 		playsound(src, open_sound, 50, TRUE)
 		for(var/atom/movable/AM in src)
 			AM.forceMove(loc)
 	else
-		set_density(TRUE)
+		REMOVE_TRAIT(src, TRAIT_UNDENSE, MIMIC_TRAIT)
 		opened = FALSE
 		icon_state = "crate"
 		playsound(src, close_sound, 50, TRUE)
diff --git a/code/modules/mob/living/simple_animal/hostile/mining_mobs/elites/pandora.dm b/code/modules/mob/living/simple_animal/hostile/mining_mobs/elites/pandora.dm
index 0fae77d08ceb..b4f171a10ceb 100644
--- a/code/modules/mob/living/simple_animal/hostile/mining_mobs/elites/pandora.dm
+++ b/code/modules/mob/living/simple_animal/hostile/mining_mobs/elites/pandora.dm
@@ -147,13 +147,13 @@
 		new /obj/effect/temp_visual/hierophant/blast/damaging/pandora(t, src)
 	animate(src, alpha = 0, time = 2, easing = EASE_OUT) //fade out
 	visible_message(span_hierophant_warning("[src] fades out!"))
-	set_density(FALSE)
+	ADD_TRAIT(src, TRAIT_UNDENSE, VANISHING_TRAIT)
 	addtimer(CALLBACK(src, PROC_REF(pandora_teleport_3), T), 2)
 
 /mob/living/simple_animal/hostile/asteroid/elite/pandora/proc/pandora_teleport_3(turf/T)
 	forceMove(T)
 	animate(src, alpha = 255, time = 2, easing = EASE_IN) //fade IN
-	set_density(TRUE)
+	REMOVE_TRAIT(src, TRAIT_UNDENSE, VANISHING_TRAIT)
 	visible_message(span_hierophant_warning("[src] fades in!"))
 
 /mob/living/simple_animal/hostile/asteroid/elite/pandora/proc/aoe_squares(target)
diff --git a/code/modules/mob/living/simple_animal/simple_animal.dm b/code/modules/mob/living/simple_animal/simple_animal.dm
index 09e3fe1f2546..ca7a5cd3832d 100644
--- a/code/modules/mob/living/simple_animal/simple_animal.dm
+++ b/code/modules/mob/living/simple_animal/simple_animal.dm
@@ -463,7 +463,7 @@
 	icon_state = icon_dead
 	if(flip_on_death)
 		transform = transform.Turn(180)
-	//ADD_TRAIT(src, TRAIT_UNDENSE, BASIC_MOB_DEATH_TRAIT)
+	ADD_TRAIT(src, TRAIT_UNDENSE, BASIC_MOB_DEATH_TRAIT)
 	return ..()
 
 /mob/living/simple_animal/proc/CanAttack(atom/the_target)
@@ -488,7 +488,7 @@
 	if(!.)
 		return
 	icon_state = icon_living
-	set_density(initial(density))
+	REMOVE_TRAIT(src, TRAIT_UNDENSE, BASIC_MOB_DEATH_TRAIT)
 
 /mob/living/simple_animal/proc/make_babies() // <3 <3 <3
 	if(gender != FEMALE || stat || next_scan_time > world.time || !childtype || !animal_species || !SSticker.IsRoundInProgress())
diff --git a/code/modules/pai/shell.dm b/code/modules/pai/shell.dm
index 711e19ead51b..665727705eba 100644
--- a/code/modules/pai/shell.dm
+++ b/code/modules/pai/shell.dm
@@ -93,7 +93,7 @@
 	card.forceMove(target)
 	forceMove(card)
 	add_traits(list(TRAIT_IMMOBILIZED, TRAIT_HANDS_BLOCKED), PAI_FOLDED)
-	set_density(FALSE)
+	ADD_TRAIT(src, TRAIT_UNDENSE, PAI_FOLDED)
 	set_light_on(FALSE)
 	holoform = FALSE
 	set_resting(resting)
@@ -124,7 +124,7 @@
 	addtimer(VARSET_CALLBACK(src, holochassis_ready, TRUE), HOLOCHASSIS_COOLDOWN)
 	REMOVE_TRAIT(src, TRAIT_IMMOBILIZED, PAI_FOLDED)
 	REMOVE_TRAIT(src, TRAIT_HANDS_BLOCKED, PAI_FOLDED)
-	set_density(TRUE)
+	REMOVE_TRAIT(src, TRAIT_UNDENSE, PAI_FOLDED)
 	if(istype(card.loc, /obj/item/modular_computer))
 		var/obj/item/modular_computer/pc = card.loc
 		pc.inserted_pai = null