baby sea hares (most likely) Chris had 3 in those rocks, but removed them. They must of laid eggs. You can trade them back to him for snails, though. They are worth about 8 to 15 bucks a piece (of course, u would have to work that out with him, and he'll still have to make a profit). Your tank won't support them for very long. I don't know how they lived through your cycle. good find!