Poisons foes when they switch in.
Toxic Spikes is a Poison-type status move that lays a trap of toxic spikes on the opponent's side of the field. When an opposing Pokémon switches in, it becomes poisoned if it is grounded. In Polished Crystal, Toxic Spikes can be learned by various Poison-type Pokémon, providing them with a strategic option to inflict poison status on opponents as they enter the battle, gradually wearing them down over time.