Concept: Sea Ghost, Sea Rug, or Sea Sloth depending on regional preference (Oceamiculum oceadicis)
The Sea Ghost (Oceamiculum oceadicis) is an opportunistic omnivore. Living mostly off algae it scrapes off coral with it's radula. It will eat the occasional soft coral and sometimes take off chunks of stoney corals. The Sea Ghost's skin is covered in chromatophores which allow it to change it's skin color to match any section off reef it moves to. Even the hard growths on the Sea Ghost are covered in a thin layer of skin, so they too can change color and pattern. The Sea Ghost's skin has another great camouflaging trick. It can stretch and manipulate it's skin to have almost any texture or protuberances it needs for each particular spot it rests on. The Sea Ghost's skin is much like some species of octopus, though it takes it a few steps farther. The coral like growths on the shoulders, spine, and other places, along with the sponge like growths on the back are all part of the animal, not actual coral or sponges. And even though the Sea Ghost has symmetry in it's camouflage, the other animals never seem to notice. And while most coral hobbyists will easily be able to tell the fake coral on the Sea Ghost is just that, fake. Animals don't notice that the Sea Ghosts evolution to mimic coral isn't perfect, but good enough to evade most all predators. With the gills of the animal located underneath like that of a sting ray, it will use the fake seapens jutting from it's shoulders for there second purpose. The feathery sea pen like structures make great camouflage, but they are also gills. So instead of kicking up sand with it's lower bottom gills when the Sea Ghost is laying on sandy areas, it can instead use the feathery gills on it's shoulders for oxygen.