ID on mysterious swimming worm

[aninjaatemyshoe]

I don't have a picture of this thing. I'll try to get one, but the damn things moves so fast... Anyway, it is a little worm-like thing that is about an inch and a half long. It has a salmon colored body and a white head. It must have little swimmerettes along its body as it moves around remarkably fast for its body shape. What the heck is it?

 

[LeslieH]

The epitoke of a polychaete worm. Some worms modify their bodies when they develop eggs or sperm so they can swim up into the water column for spawning.