An ice world is a planet, dwarf planet or moon whose surface is mostly covered by water ice or other kinds of ice. These are usually depicted as cold, desolate worlds where only specialized lifeforms can survive. In theory, any terrestrial planet located too far away from its star has the potential to be an ice world. A real world example would be the dwarf planet Pluto. Some ice worlds might have a deep ocean of liquid water hidden beneath the surface, as it's the case with Europa, a moon of Jupiter.