The NASA rover Perseverance recently discovered a strange rock on Mars, which appears to be made up of small rounded stones a few hundred millimeters in diameter. The rover is exploring the Jezero Crater, a region of Mars thought to have once been a river delta. This is not the first time such a strange rock has been discovered on the Red Planet. In the past, Martian rovers have discovered a number of strange objects that could hold important clues as to the geological history of Mars. A selfie taken by NASA’s Perseverance rover.