Fix some harddels. (#21373)

Let's try to haunt down this brain and mannequin harddel bullshit

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Co-authored-by: Matt Atlas <liermattia@gmail.com>

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

@@ -21,7 +21,7 @@
 			death(1)	//Brains can die again. AND THEY SHOULD AHA HA HA HA HA HA
 		ghostize()		//Ghostize checks for key so nothing else is necessary.
 	container = null
-	. = ..()
+	return ..()
 
 /mob/living/carbon/brain/IsAdvancedToolUser() // to be able to use weapons when piloting a hardsuit
 	return TRUE

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

@@ -19,7 +19,7 @@ INITIALIZE_IMMEDIATE(/mob/living/carbon/human/dummy/mannequin)
 
 /mob/living/carbon/human/dummy/mannequin/Destroy()
 	SSmobs.free_mannequin(src)
-	. = ..()
+	return ..()
 
 /mob/living/carbon/human/vatgrown/Initialize(mapload)
 	. = ..(mapload, SPECIES_HUMAN_VATGROWN)

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

@@ -66,9 +66,6 @@
 	var/toxloss = 0
 	var/datum/reagents/metabolism/ingested
 
-/mob/living/carbon/slime/get_ingested_reagents()
-	return ingested
-
 /mob/living/carbon/slime/Initialize(mapload, colour = "grey")
 	. = ..()
 
@@ -90,6 +87,19 @@
 	last_AI = world.time
 	regenerate_icons()
 
+/mob/living/carbon/slime/Destroy()
+	victim = null
+	target = null
+	leader = null
+	for(var/mob/friend in friends)
+		friends -= friend
+	friends.Cut()
+	QDEL_NULL(ingested)
+	return ..()
+
+/mob/living/carbon/slime/get_ingested_reagents()
+	return ingested
+
 /mob/living/carbon/slime/purple/Initialize(mapload, colour = "purple")
 	. = ..()