Contrary is a Pokémon ability introduced in the fifth generation. Pokémon with this ability have reverse stat changes.
In battle, Pokémon with Contrary invert all the stats changes it receives. If an effect would lower a stat, this Pokémon would increase that stat. If an effect would increase a stat, the stat is increased. Self-inflicted changes are inverted as well. Status effects like burn are not affected by Contrary. Stat changes carried by Baton Pass remain the same
Stat boosts from Z-Moves are not inverted by Contrary with the exception of Extreme Evoboost, which inverts those stat changes. Mist and stat protecting effects take account the inversion before blocking a stat change. Pokémon with Mold Breaker ignore the inversion.