A cryovolcano is an icy volcano. These goelogical structures are known to have formed on frozen/icy celestial bodies.
cryovolcano
Pluto appears to have two cryovolcanoes.A cryovolcano (colloquially known as an ice volcano) is a theoretical type of volcano that erupts volatiles such as water, ammonia or methane, instead of molten rock. ... Cryovolcanoes may potentially form on icy moons and other objects with abundant water past the Solar System's snow line (such as Pluto).