Generation V
Sap Sipper
Boosts Attack when hit by a Grass-type move.
Detailed Effect
Whenever a Grass-type move hits this Pokémon, its Attack rises one stage, negating any other effect on it.
Pokémon With Sap Sipper
21 canonical Pokémon forms can have this Ability.

Deerling
Sawsbuck
Bouffalant
Skiddo
Gogoat
Goomy
Sliggoo
Goodra
Drampa
Hisuian Sliggoo
Hisuian Goodra
Marill 
Azumarill
Girafarig
Stantler
Miltank
Azurill
Blitzle 
Zebstrika
Wyrdeer
Farigiraf