Is it a rock? A trick of Martian light on the eye? Or Osama Bin Laden waving from his barren hideout 300 million miles from planet earth?
NASA scientists have been puzzled by the peculiarly life-like image which has been beamed back to earth by one of their two robot rovers that are currently trundling about the surface of the red planet, on the hunt for clues of life on Mars.
It will delight spacewatchers who have been so far disappointed by the lack of images of little green men captured by the twin vehicles on their four year mission.
The alien figure was pictured at the far left of one of the panoramic photographs taken by the exploration rover, Spirit, from the top of a low plateau in late 2007.
The robot vehicle and its twin, Opportunity, have been roving around on Mars since completing their first successful mission in April 2004. Their principle goal is to hunt for geological evidence of water, that suggest an environment which may once have been hospitable to life.
Having been launched from Cape Canaveral, in Florida, in June and July in 2003, they travelled 487 million and 456 million km respectively to opposite ends of the planet, where they went on to explore the dusty, rock-strewn landscape.
Each solar-powered rover is a sort of the mechanical equivalent of a geologist walking the surface of Mars. The mast-mounted cameras are mounted 1.5 meters(5 feet) high and provide 360-degree, stereoscopic, humanlike views of the terrain.
The robotic arm is capable of movement in much the same way as a human arm with an elbow and wrist, and can place instruments directly up against rock and soil targets of interest. In the mechanical "fist" of the arm is a microscopic camera that serves the same purpose as a geologist's handheld magnifying lens.
The budget for the project is around $820million.
Last week, a similar probe captured the first images from the "dark side" of Mercury, which showed previously unseen hemisphere from 17,000 miles.