Merge pull request #2607 from adrix89/Fix_1653

Fix 1653

code/game/objects/effects/spiders.dm

@@ -93,7 +93,7 @@
 	desc = "It never stays still for long."
 	icon_state = "spiderling"
 	anchored = 0
-	layer = 2.7
+	layer = 2.75
 	health = 3
 	var/amount_grown = 0
 	var/grow_as = null

code/game/objects/structures/grille.dm

@@ -89,7 +89,7 @@
 	if(istype(mover) && mover.checkpass(PASSGRILLE))
 		return 1
 	else
-		if(istype(mover, /obj/item/projectile))
+		if(istype(mover, /obj/item/projectile) && density)
 			return prob(30)
 		else
 			return !density

code/modules/projectiles/projectile.dm

@@ -146,7 +146,7 @@
 				return
 			step_towards(src, current)
 			sleep(1)
-			if(!bumped && !isturf(original))
+			if(!bumped && (original.layer>=2.75 || ismob(original)))
 				if(loc == get_turf(original))
 					if(!(original in permutated))
 						Bump(original)