Lava

Lava is magma that has been expelled from the interior of a terrestrial planet or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or underwater, usually at temperatures from 800 to 1,200 °C. Lava may be erupted directly onto the land surface or onto the sea floor or it may be ejected into the atmosphere before falling back down. The solid volca... (Wikipedia)