An old snapshot taken by Mars Rover Spirit seems to contain a mysterious figure walking downhill. Take a look at the picture and judge for yourself if it’s really an alien or just an odd rock formation.

check the dailymail.co.uk article for more and a higher resolution image of the above.

EDIT: I tracked down the original NASA image, you can watch it here (Resolution: 12756 x 3487, Size: 5.6MB); the “formation” is indeed visible on the lower left side, so at least it’s not a Photoshop fake