diff --git a/code/modules/mob/abilities.dm b/code/modules/mob/abilities.dm
index 2325e0c0d1e..cd92b501e44 100644
--- a/code/modules/mob/abilities.dm
+++ b/code/modules/mob/abilities.dm
@@ -12,8 +12,8 @@ Creature-level abilities.
 	set desc = "The ability to crawl through vents if naked and not holding anything."
 
 
-	if(istype(src,/mob/living/carbon/human/slime))
-		var/mob/living/carbon/M = src
+	if(istype(usr,/mob/living/carbon/human/slime))
+		var/mob/living/carbon/human/slime/M = usr
 		// Check if the client has a mob and if the mob is valid and alive.
 		if(M.stat==2)
 			M << "\red You must be corporeal and alive to do that."
@@ -33,3 +33,5 @@ Creature-level abilities.
 			return 0
 
 		M.handle_ventcrawl()
+	else
+		src << "This should not be happening. At all."
\ No newline at end of file