Came home from work tonight and wife shows me the belong picture. Says she watched it crawl out from the rock shown, cut off some of my polyps that we're trying to grow back and sneak back under the rock.
I've never seen anything like this in my minor years of mild experience. She said it sorta moved like a crab but we never bought no crab that looks like this.
What is it? And advice as to what to do about it?

I've never seen anything like this in my minor years of mild experience. She said it sorta moved like a crab but we never bought no crab that looks like this.
What is it? And advice as to what to do about it?
