The latest issue of Science has a paper [subscription required] describing the movement of the sandfish lizard, a desert reptile that can swim through sand, to cool off or escape predators, by wiggling like an eel. Check out the cool vids from the supplementary material:
Video 1: The sandfish burying itself in the sand
Video 2: X-ray cinematography of the sandfish sub-surface locomotion.
Videos should be free to access, but may require Quicktime.
[h/t: Why Evolution is True, who also includes a neat paper about tiger moths who 'jam' the sonar of predatory bats]