feather duster like

So I got this hairy mushroom coral about a week ago and noticed a few feather duster looking things on it. Except I’m worried they might be aipstasia. There’s about 3 of them from what I can see. I dip all my corals but know feather dusters sometimes survive and aiptasia definitely will survive...

I have recently noticed a feather duster like animal living inside the “stalk” of my new Duncan coral. There looks to be a small white hole in the coral where the “feather duster”pokes out. Is this critter harmless and if so how would I go about removing it from the coral? Any input is...

found this little guy today by accident. Came along with my pretty mushroom rock. Any idea what it is? Think it will hurt my mushrooms?

Assuming I've got what looks like a feather duster worm on the underside of my superman ricordea. Is this the case? Safe to leave there or should I remove it?

I keep finding these white fuzzy type things all over my rocks and I’m concerned about what they are, hopefully you can tell what they are in the pictures, if not I will try and take better photos