Xenobio fixes

code/modules/ai/ai_holder_movement.dm

@@ -145,6 +145,8 @@
 
 // Wanders randomly in cardinal directions.
 /datum/ai_holder/proc/handle_wander_movement()
+	if(!holder)
+		return
 	ai_log("handle_wander_movement() : Entered.", AI_LOG_TRACE)
 	if(isturf(holder.loc) && can_act())
 		wander_delay--
@@ -164,13 +166,13 @@
 	// No target, don't use the ladder
 	// Target is visible, don't use the ladder
 	if(!target || can_see_target(target))
-		return 
+		return
 
 	var/has_hands = TRUE
 	if(istype(holder, /mob/living/simple_mob))
 		var/mob/living/simple_mob/S = holder
 		has_hands = S.has_hands
-	
+
 	// Don't have means to use a ladder or the space around it, don't use the ladder
 	if(!has_hands && !holder.hovering)
 		return
@@ -178,7 +180,7 @@
 	var/obj/structure/ladder/L = locate() in get_turf(holder)
 	if(!istype(L))
 		return // No ladder, can't use it
-	
+
 	if(!holder.may_climb_ladders(L))
 		return // Can't climb the ladder for other reasons (Probably inconsequential?)
 
@@ -187,6 +189,6 @@
 		directions += L.target_down
 	if(L.allowed_directions & UP)
 		directions += L.target_up
-	
+
 	if(directions.len)
 		L.climbLadder(holder, pick(directions))

code/modules/mob/living/simple_mob/subtypes/slime/xenobio/xenobio.dm

@@ -225,7 +225,11 @@
 				if(T.density) // No walls.
 					continue
 				for(var/atom/movable/AM in T)
-					if(AM.density || istype(AM, /mob/living/simple_mob/slime))
+					if(istype(AM, /mob/living/simple_mob/slime) || !(AM.CanPass(src, T)))
+						free = FALSE
+						break
+				for(var/atom/movable/AM in get_turf(src))
+					if(!(AM.CanPass(src, T)) && !(AM == src))
 						free = FALSE
 						break
 
@@ -238,7 +242,7 @@
 
 			var/list/babies = list()
 			for(var/i = 1 to split_amount)
-				babies.Add(make_new_slime())
+				babies.Add(make_new_slime(no_step = i))
 
 			var/mob/living/simple_mob/slime/new_slime = pick(babies)
 			new_slime.universal_speak = universal_speak
@@ -253,7 +257,7 @@
 		to_chat(src, span("warning", "I have not evolved enough to reproduce yet..."))
 
 // Used when reproducing or dying.
-/mob/living/simple_mob/slime/xenobio/proc/make_new_slime(var/desired_type)
+/mob/living/simple_mob/slime/xenobio/proc/make_new_slime(var/desired_type, var/no_step)
 	var/t = src.type
 	if(desired_type)
 		t = desired_type
@@ -275,7 +279,8 @@
 	baby.faction = faction
 	baby.friends = friends.Copy()
 
-	step_away(baby, src)
+	if(no_step != 1)
+		step_away(baby, src)
 	return baby
 
 /mob/living/simple_mob/slime/xenobio/get_description_interaction()