Identify this hitchhiker

So I've had my trump coral in my tank for just over two weeks. Today while looking at the tank, I saw this little purple thing with two black eyes and two very small antennae. He is inside a tiny hole (branch) of the stony part of the trumpet coral. Best pick I could get, its the same color as the purple part of a Royal Gramma. Couldn't find anything hitchhiker guides.











And no my trumpets aren't bleached, just bright looking due to camera phone.