Since NASA's Curiosity rover touched down on the Red Planet two weeks ago and powered up its cameras, it has already managed to photograph several alleged UFOs and other "anomalies" in the surrounding landscape.

From classic flying saucers to an absurdly out-of-place fossilized human finger, here's a rundown of what UFO believers claim to have found in Curiosity photos so far. [ Gallery of Mars 'UFO' Photos ]

Horizon anomaly (aka impact cloud)
Speculation about Martians in Curiosity's midst got off to a running start when the very first sequence of photos taken by the rover raised questions. A hazy, distant object mysteriously appeared and then disappeared in consecutive images of the Martian horizon, perplexing even NASA scientists at first.

But the much-discussed "anomaly" turned out not to be a sign of alien activity, but rather the plume of dust kicked up by the sky crane that delivered the rover close to the Martian surface, then veered off and struck the ground some 2,000 feet (600 meters) away.