Your link doesn't work but I worked on the previous version.
(In your capx Spiderbullet wasn't a clone, it had the tower behavior)
I removed the clone, now "Spidertower" = "Spiderbullet" (it has both behaviors, tower and bullet)
You have to add the bullet behavior to the Spiderbullet sprite AND set the initial state of the bullet behavior to Disabled
You should add the Destroy outside layout behavior to.