Moxie

Moxie raises the Pokemon's Attack by one stage each time it knocks out another Pokemon, introduced in Generation V. This includes knocking out allied Pokemon in Double Battles, though the boost only triggers from direct KOs -- indirect causes like poison damage, entry hazards, or weather do not activate it.

The Attack boost stacks with each successive KO, enabling a snowball effect where the Pokemon becomes increasingly powerful as it sweeps through a team. If a Moxie user knocks out a Pokemon with Mummy, the attacker's ability changes to Mummy and the Moxie boost is lost for that KO. The ability also does not activate if the user faints from recoil damage on the same turn it scores a KO.

Moxie is found on 16 Pokemon, including prominent physical sweepers like Gyarados, Salamence, Krookodile, and Heracross. It is one of the most feared sweeping abilities in competitive play -- once a Moxie user scores its first KO, each subsequent one becomes easier due to the compounding Attack boosts. Choice Scarf Moxie users are particularly dangerous, combining outspeeding threats with escalating power that can clean up weakened teams in a single turn sequence.