Permafrost is a non-damaging Ice-type move. It is available as TM105 in-game.
Permafrost is an entry hazard that has a 1/5 chance of freezing the opponent's Pokémon upon switch in. If the opponent switches in an Ice-type Pokémon then the hazard is absorbed and the effect disappears until it is used again.
1) Frost covers the ground around the foe, randomly freezing foes who switch in.
2) The ground freezes at the foes [sic] feet, giving a chance to freeze any for who switches in.