After a little more digging it does look to be a Saint Thomas Warty Bubble. Neato! Very strange looking for what it is though. I have never seen one quite like this. Guess that means I should probably take it off its plug and get it on the ground huh? Also this image is the closest I found to it, image credits to www.marineworldindia.com/
I would not take it off the plug, they are not easily glued down. It probably grew on to that plug after someone placed plugs close to reproducing corallimorphia. :-)
Yea he's been kind of moving between two spots on it. But low light on the bottom would probably be a good place for it instead of mid way on the tank? I read somewhere that if they get a little more light their tentacles will grow thicker, but if they get less light then the body will get wider and tentacles might grow a little more upwards. Not sure how much of that is true being that I don't have any experience with corallimorphs at all. Also, can they be fed mysis shrimp. That's what I feed my clowns so that would make things easier.