So I have these 2 things on my hammer. They’ve been there for a while and I thought they were just some crust of some sort flaking off. Now I see that the underside of them actually has white growth and to me it seems to be some type of mollusk. Does anyone have any clue? Don’t mind the GHA, vermitid and I think an old barnacle. I do want to mention that when I shine a light on it at night, it does close up. The pics below are night shots where the “mouth” is open.