This image was found among several of the images taken by NASA's Mars Curiosity rover. The amateur astronomer on ArtAlienTV claims that this is a large rodent of about 2-3 feet in length.
Watch the video for an enhanced view of the "mouse" as well as a few other anomalies, including a big rock that you can kind of see has a scary face if you look at the right angle.
Is this evidence of life on Mars? There are some who want to believe, but NASA hasn't mentioned any Rodents of Unusual Size in their findings.
For now, enjoy this artists rendering of the space mouse.