First pic looks like a small feather duster type worm. If so, harmless filter feeder.
if you're talking about the white circular things, sponges maybe?
i agree, the first one looks like a feather duster. nice!
It might be aiptasia? Type of anemone. Comes as a hitchhiker and spreads quickly. Most guys kill them as a pest. Does it retract into a hole quickly if you go near it?
Feather duster in the first pic