DO NOT CUT it. You will regret it. If it were me, I would take the rock out and zap him with some aipastia X. I would do this in a separate container too with saltwater in it. Any piece of an aipastia will grow back and they can spout out spores that will result in dozens more. I am fighting a losing battle right now with them and will most likely have to get all new rock. And it all started with a single aipastia on a single coral that I didnt zap adequately and now I have hundreds, and thats no exageration.