Worm colonies, Need an ID

[Elum]

I have these worms on my LR that seem to live in colonies attached at the base and collect food and draw it back into the colony. They can also move around and spread, they started as just 1 colony living in what looked like an old Barnacle, they survived the cycle process in my tank and seem to be flourishing (tank is a little over 2 months old now). I cant confirm if they are damaging, but i think they could be eating my coraline, which if thats the case i would like to get rid of them.
Probable by buying a natural predator, so far i have 2 yellow tail damsels and a Gonodactylaceus falcatus Mantis shrimp. And they just seem to ignore them...

Can you please try and ID them for me, and suggest ways to get rid of them.
My camera sux so i cant get any good shots of the colonies themselves, however i managed to rip one off the rock with tweasers and get some visible pics. I can try harder to get some of the colonies if this isnt enough for an ID.

 

[LeslieH]

It can't be proven from the image but I believe that's just one of the many feeding tentacles belonging to a single terebellid polychaete, AKA spagetti worm. The body is hidden in a tube tucked away inside a crevice. Here's a good photo of an exposed one by my friend Brian http://www.flickr.com/photos/brianmayes/3673694524/

 

[Elum]

you could be right, i have seen tentacle displays similar to that but the colours are different. The worm/tentacle seemed to die instantly after i broke it off, they seem to move completely independent of one another and are spread over several locations, could just be multiple multitentacle worms.
Also i forgot to mention, once they have drawn in enough food and probably digest it, they expel it into the current, at first i thought it was spores or something. But i now believe it is just their waste.