I recently purchased this Halloween hermit approx 2 weeks ago. I noticed at that time something on its shell but didn't think too much of it. Today I noticed whatever was on its shell appeared to he falling off/opening up. I decided to see if I could push it off the shell and it quickly snapped shut/adhered back to the hermits shell. I believe this is some kind of clam and there was 2 of them at one point, but one Is dead and hanging open. Should I leave it where it is? Try to scrape it off and mount to the rocks? Is it a pest of some kind? Thanks in advance for any replies!