What's this of giant spider silk? Why not hill titan or forgotten beast!? In my last fort I captured an unkillable cloth titan that would spam webs. Not even lava could take it down. I'd use it to spam webs at a kitten chained to a pedestal. Most of the webs were set up to fall about fifteen levels so my workers down there could harvest without seeing the titan and the titan couldn't step down. I didn't even need an army in that fort. I would release the titan from time to time to murder sieges and ambushes then draw it back in with a kitten.
In all seriousness though that's a random spawn and probably tough to get. I'd probably suggest a wild spider and use a kitten or some other animal that can't starve on a platform. I'd just personally prefer having my friendly creature being shot at and the hostile one behind unbreakable fortifications.
I never considered a web turret before. Can those webs be harvested?
