Berserk

https://vignette.wikia.nocookie.net/pmysteryuniverse/images/4/44/Berserk.png/revision/latest?cb=20200123083532&format=original Berserk is an Ability that affects the Special Attack stat.

Effect
If the Pokémon with this Ability takes damage from an attack equal to 50% or more of its maximum HP, its Special Attack stat is raised by one stage.

Pokémon with

 * Drampa