I got this rock???? at FishScales for my wife. Actually I bought her a feather duster and Julie threw this in because it had some small feather dusters encrusted on it. Well a few days later my wife noticed that the rock????? had opened up. Also noticed it has some worm shaped resident inside. Cannot get a good look, only opens up a small crack. Seems to open at the point of the egg shaped whatever, like a beak. Some sort of clam or mollusk? Anybody have any ideas.