Squat lobster on pink sponge. Although he is a type of lobster, this little guy is very small, about 1 or 2cm if I remember correctly. He lives on the pink sponge (yes like the one you wash your face with but alive, fleshy and underwater) and hides from predators in the folds of the sponge. The sponges can grow quite large so often you find two or three of these little lobsters on one sponge.
Taken underwater in Raja Ampat, Indonesia with D300 and 105 VR macro lens