Generation Vii
Grassy Surge
Turns the ground into Grassy Terrain when the Pokémon enters a battle.
Detailed Effect
When this Pokémon enters battle, it changes the terrain to Grassy Terrain.
Pokémon With Grassy Surge
5 canonical Pokémon forms can have this Ability.

Tapu Bulu
Grookey
Thwackey
Rillaboom
Rillaboom Gmax