The Mars Phoenix Lander has finally spotted some dust devils!
The camera shot these four frames, 50 seconds between each frame, so you are seeing the movement over about two and a half minutes. It's about a kilometer away from the lander and meters in diameter. You may even notice some changes in the shadows in the different frames due to some clouds passing by. Another neat measurement is that they managed to record air pressure changes as they dust devils passed.
Dust devils have been seen before by other landers on Mars and were expected to be seen here based on evidence in images from orbiters. Remember that all other landers on Mars have landed near the equator...Phoenix landed up north of the arctic circle, so this is a different part of the planet.
Unfortunately, since it is so far north and the northern hemisphere of Mars is heading into winter, the nights are getting longer and colder. Soon the solar panels won't be able to recharge the batteries and Phoenix will go silent. We knew this would happen of course, and it already has exceeded its 90 day primary mission and met its major science objectives (and thrown a couple of new mysteries our way to boot).