Last week, I saw what looked like a segmented worm at first nestled in some fire coral and writhing with the surge, in the Turks and Caicos islands in the Caribbean.
It only looked like a worm from far away, when I got closer it looked like some sort of rock anemone or carpet anemone, only I've never seen a carpet anemone with branching tentacles, and I didn't see the center of a rock anemone, just lots of edges folded over each other. Here's the best picture I got of it:

Turks and Caicos by davelewinn, on Flickr

