Keen-eyed alien hunters have been examining snaps taken by the space agency’s robot Opportunity.
In one shot, a dark object is visible along the slopes of one of Mars’ craters.
Truthers believe it is a statue and point to a supposed long arm, a bulky chest and two “leg fragments”.
One person wrote on YouTube: “(It) looks like an actual statue. There seem to be so many anomaly stones on Mars that at some point, one must admit that sometimes a rock is an ancient artefact.”
Another conspiracist wrote: “The head by itself kind of looks Egyptian. Mars could have been Earth number one.”
Others suggested the outline may even be a corpse.
One user commented: “Statue!? How long would it take a lifeform to decompose?”
Earlier this month, an ancient system of lakes was discovered on the Red planet.
A growing body of evidence shows the Red Planet was once covered in water, above and below ground, creating good conditions for life to survive.
Water would be key for aliens to thrive and scientists have been trying to track it down on the planet.
The Red Planet's surface is largely dry and desolate today, but information gathered by the European Space Agency’s Mars Express mission shows this has not always been the case.
The scientists say they have located an underground water complex that was previously predicted by computer models.