Yeah just some kind tube worm / feather duster etc and just filter feeder like already said above.
My attitude is If something isn't bothering anything and is beneficial then just leave it be ^_^
I used to have lots little tube worms but since got my cbb haven't seen any in a long time so think he slurped them up lol.
Got about 5 little aiptasia on a zoa frag ,really small at momemt,like nearly as big as the zoa polyps and not touched them yet lol
So now got decision do I inject boiling hot rodi into them once place zoa frag in a container before I move to permanent position and risk irritating them so they release spores and make babies, that's if the boiling hot water doesn't work or I don't do right as never done before,like they so tiny they retract and can't see the little buggers ha ha