adds spider_vr.dm

tiny bit of code to do everything they have to do.

code/game/objects/effects/spider_vr.dm

@@ -0,0 +1,13 @@
+/obj/effect/spider/spiderling/grub
+	name = "grub larva"
+	desc = "It never stays still for long."
+	//M.icon = 'grub_vr.dmi'
+	icon_state = "spiderling"
+
+obj/effect/spider/spiderling/grub/process()
+	if(amount_grown >= 100)
+		var/spawn_type = /mob/living/simple_animal/retaliate/solargrub
+		new spawn_type(src.loc, src)
+		qdel(src)
+	else
+		..()