Generation V
Rattled
Some move types scare it and boost its Speed.
Detailed Effect
This Pokémon's Speed rises one stage with each hit from a damaging Dark-, Ghost-, or Bug-type move.
Pokémon With Rattled
21 canonical Pokémon forms can have this Ability.

Toxel 
Wiglett 
Wugtrio
Gimmighoul
Basculin White Striped
Magikarp
Ledyba
Sudowoodo
Dunsparce
Snubbull
Granbull
Poochyena
Whismur
Clamperl
Bonsly
Cubchoo
Yamper
Dudunsparce Two Segment
Alolan Meowth
Alolan Persian
Dudunsparce Three Segment