When a stat of a Pokémon with this Ability is lowered by an opponent, its Special Attack is increased by two stages. Competitive will not activate if the Pokémon with this Ability lowers its own stats (such as with Close Combat) or if its stats are lowered by an ally.
If multiple stats are lowered (such as by Memento or Venom Drench) Competitive activates for each stat lowered.
If the Pokémon with this Ability is holding a White Herb, if a stat other than Special Attack is lowered, Competitive will trigger before the White Herb, so the user will receive the Special Attack boost and then the lowered stat will be restored. If its Special Attack is lowered, Competitive will activate first, increasing its Special Attack so that the White Herb cannot activate.