FusionDex

Most of Numer's body volume consists of a sac that can hold all sorts of things: water, air, magma, and even stone. By inhaling matter into its sac, Numer can change its buoyancy; by expelling it, Numer can use powerful moves, too.

While this Pokémon usually lives in the sea, it can survive on land, although not too long. A Numer stores boiling magma in the hump on its back.