Looks like the feeder of a vermetid snail. Try to find the bottom of its tube abd break off at the base. If you cant find the base, and can see the tube, place a dab of gel super glue from dollar store over the opening of tube and snail will either get stuck to glue or stuck in hole and starve off. These can colonize so get rif of it now
Hi, I see this is an old thread, but are you referring to the clump of worm things underneath the antenna? To me they almost look like tentacles belonging to an anemone or something…