Fixes glowshroom runtimes. (#52120)

code/game/objects/effects/glowshroom.dm

@@ -45,11 +45,6 @@
 	. = ..()
 	. += "This is a [generation]\th generation [name]!"
 
-/obj/structure/glowshroom/Destroy()
-	if(myseed)
-		QDEL_NULL(myseed)
-	return ..()
-
 /**
   *	Creates a new glowshroom structure.
   *
@@ -142,6 +137,8 @@
 				continue
 
 			Decay(TRUE, 2) // Decay before spawning new mushrooms to reduce their endurance
+			if(QDELETED(src))	//Decay can end us
+				return
 			var/obj/structure/glowshroom/child = new type(newLoc, myseed, TRUE, TRUE)
 			child.generation = generation + 1
 			shrooms_planted++