Throw this out for a wider audience. This was our second "free" hitchiker pest. The wife and I had no idea what this thing was at first.
Our very first "free" live rock pest? Majanos. Hah. Gotta learn somehow I guess.
You don't like lionfish do you? lol! They are some of my favorite marine fish. They are gorgeous and love all of the pictures of them. I'm very envious!