diff --git a/code/game/objects/effects/spiders.dm b/code/game/objects/effects/spiders.dm
index 8545ca174e..db61554bd1 100644
--- a/code/game/objects/effects/spiders.dm
+++ b/code/game/objects/effects/spiders.dm
@@ -269,7 +269,7 @@
 				walk_to(src, target_atom, 5)
 				if(prob(25))
 					src.visible_message("<span class='notice'>\The [src] skitters[pick(" away"," around","")].</span>")
-		else if(prob(5))
+		else if(amount_grown < 75 && prob(5))
 			//vent crawl!
 			for(var/obj/machinery/atmospherics/unary/vent_pump/v in view(7,src))
 				if(!v.welded)