An odd-looking bit of rock mysteriously appeared in front of Opportunity rover, waiting out the Martian winter, taken by Opportunity Mars rover on Sol (Martian day) 3540 or January 8 Earth time, according to NASA’s website.

Left: a photo taken 3528 days after the Opportunity rover arrival to Mars. Right: the exact same spot 12 Mars days later. Notice the difference? NASA JPL scientists did too: "It's about the size of a jelly doughnut. It was a total surprise, we were like 'wait a second, that wasn't there before, it can't be right. Oh my god! It wasn't there before!' We were absolutely startled."

An odd-looking bit of rock mysteriously appeared in front of Opportunity rover in the beginning of January as the rover, waiting out the Martian winter, has not moved since the end of November, according to NASA. The rock suddenly appeared on photographs taken by Opportunity Mars rover on Sol (Martian day) 3540 or January 8 Earth time, according to NASA’s website. Photographs previously taken on Sol 3536 showed no trace of the rock. The body was named 'Pinnacle Island', according to Opportunity’s Pancam database descriptions.