Help Identify White Tubes?

[Noober]

Hey I will take a pic of this sooner or later unless this really hits home with one of you guys. I think that I can describe it fairly well. Anyway I have these tube things that look just like a small feather duster, except the tubes look like they are bits and pieces of sand, they come out of live rock. They have two hairs coming out of them, any clues to what they might be. It looks like a crawdad (crawfish) nest in the mud next to a tank, as if it was built up with sand somehow. Like i said it has two hair/tenticles coming out of it at certain times. They are spreading decently around the tank, just thought I'd try to catch a problem early if possible, thanks a lot!

[Mr3plus1]

its not a sponge is it?

[SoLiD]

Pictures always help. Post some to your photobucket then display the picture here.

[Kyle46N]

I know exactly what you are talking about. Those two tentacles will pick up food. I always thought they were some sort of worm that picked up pieces of sand for its tube, kind of like a feather duster.