critters with antennae?

[wsoldier]

Found these large bodies with what looks like antennae growing in my sump. Are these bristle worm larvae?

Thanks in advance.

 

[Sierra_Bravo]

Pineapple sponges - good filter feeder. What look like antennae are actually a ring of filaments around the siphon opening.

The other smaller spiraling animals attached to the glass are spirorbid worms, another filter feeder.

 

[Suttonwt]

So these things appeared suddenly and are on the verge of taking over. I don't mind a few but this is getting ridiculous. How do I severely reduce the population of these sponges?