Ceres

"'The largest object in the asteroid belt, Ceres was actually thought to be a planet before more and more objects were discovered in its orbit, leading to the discovery of the asteroid belt itself.""A mix of ice and rock, Ceres is believed to have massive ice volcanoes on its surface, spraying ice up from the surface. It is believed by many that this effect produced the bright spots discovered by the Dawn spacecraft in 2015.'"