Found this in a creek while hunting for water bugs. On the one hand, it sometimes moved by extending and contracting, kind of like a worm. On the other hand, it sometimes crept along using what appear to be feet, and looks like it has a pair of something like uropods (if that's its tail) or antennae (if that's its head). Is this an arthropod (perhaps a larva), or is it some kind of segmented worm? I couldn't tell for sure which end was the head, it seemed willing to move either direction, although it seemed to prefer moving as if the end with the tendrils was the tail. Also, when disturbed it tended to lash back and forth vigorously.