WOW you guys scared me!!!!!!!!!!!!!!!!!!!!!!!!!!
I took a look, for an hour lol, and saw they are stiff and hard and inanimate....PHEW!!!
Anyways i also felt it and think it may be the rock that under coming through? Because these have been on my sand bed for about a week and a half and daily I flip them to make sure sand gets off of it. Now realizing it, it probly was closed while sand was on it so probly about 80% of time it was closed, maybe making it recede and rock coming through? well idk but i moved them up to rock and now they are opening like crazy, and shouldnt have put in sand with my diamond goby. Anyways thanks guys and i think i answered my question. Lol