When a Pokémon with this Ability is hit by a Bug-, Dark-, or Ghost-type damaging move, its Speed is increased by one stage. No immunity is granted to these types of moves, however.
If a Pokémon with this Ability is hit by a Bug-, Dark-, or Ghost-type multistrike move, each hit activates this Ability.
Generation VIII
Rattled now also activates if a Pokémon with this Ability has its stats lowered by Intimidate.