Stealth Rock

Spreads sharp rocks around the opposing field, damaging any Pokémon that enters the field for 1/8 its max HP. This damage is affected by the entering Pokémon's susceptibility to Rock moves, instead causing 1/4 max HP damage if the Pokémon has a single weakness to Rock; 1/2 max HP damage if the Pokémon has a double weakness to Rock; 1/16 max HP damage if the Pokémon singly resists Rock; and 1/32 max HP damage if the Pokémon doubly resists Rock.

Rapid Spin removes this effect from its user's side of the field. Defog will remove this effect from both sides of the field.