When a Pokémon with this Ability is hit by a physical move, Toxic Spikes are set on the opposing side of the field. If an attack would cause more than two layers of Toxic Spikes to be set or hits the substitute instead, the Ability does not activate.
If a Pokémon with this Ability is hit by a physical multistrike move (such as Fury Swipes), each hit will activate this Ability.