worm/slug id?

[lukasnca]

I have some sort of worm in my tank that hides in one of the holes in my live rock. It barely comes out so I can't take a picture but it:
(1) Looks very large (about 1/2" in thickness)
(2) Is multicolored (colors like in an oil slick)
(3) Has what look like white/beige spikes sticking out of it
(4) Is sensitive to light -- zips back in its hole fast

Any ideas?

Thanks,
Luke.

 

[Atari]

Most likely a bristleworm.

 

[Overstocker]

http://www.reefs.org/hhfaq/pages/main_pages/faq_rock1.htm

 

[lukasnca]

That's the first place I went when I saw the thing but it wasn't on the list so I posted here. Thanks anyway.