Inchworm on the Sand

[Tom Servo]

I was watching my fish eat and I noticed something that closely resembled an inchworm on the sand. I thought it was a piece of detritus by the way it was colored and textured, but it kept moving inch by inch the way the worm by that name might. It was about 1-2 cm long, about as wide as a spagetti strand, and had a small black mark at what I assumed to be the head. I couldn't get a picture because when I looked away, he'd crawled back under a rock. Any guesses?

 

[Anonymous]

I have these in my tank too. Sometimes they back up in reverse in a perfectly coordinated way. I have no idea what they are though. I just file them under "Polychaete worm".