Tubeworms are interesting little creatures. These ones came as hitchhikers on my reefer tank. I’m posting this because Facebook downscaled my gif, which is a bit lame. Update: I went back and a higher res version was available. Ah well.
This little gif shows a few stills of the creatures wafting in the current; the camera is also moving, so you can get a sense of depth, like an owl. Don’t look at it too long - you might get seasick.
See also tubeworm anatomy.