A strange "jelly doughnut" like rock on Mars that was spotted by the Opportunity rover on Jan. 8, 2014 that was not previously there four days earlier. The unexpected appearance of the mystery rock stirred up speculations about alien rock throwers and meteorite impact. The controversy even let to a concerned citizen filing a lawsuit against NASA, claiming that the space agency failed to properly investigate a possible fungus growing on the Red Planet.

However, scientists working with the intrepid robot were able to confirm afterwards that Pinnacle Island was simply kicked up by one of Opportunity's wheels as it made its way across the planet's surface. The rock has very high levels of sulfur and manganese. Both of those elements are water-soluble, suggesting that they were concentrated in the rock due to the "action of water. The rock is located in a spot on "Murray Ridge" along the wall of Endeavour Crater, where Opportunity was spending the Martian winter.