ID please

[rev]

what is this on my live rock?

 

[kdfrosty]

It's a hitchhiking featherduster

 

[salty cheese]

Coraline?
A better description would help.

 

[blemmy_guy]

Yep and it wont get much bigger in my experience. I have several of them in my tank too.
Todd

 

[thomas712]

Its a worm, and a very nice one too.