Ability
Grassy Surge
On switch-in, this Pokemon summons Grassy Terrain.
Terrain Grassy Terrain
Lasts 5 turns (8 with Terrain Extender). Grass-type moves used by grounded Pokémon deal 1.3× damage. At the end of each turn, grounded Pokémon heal 1/16 of their max HP. Earthquake, Bulldoze and Magnitude deal half damage to grounded targets.
Only one terrain can be active at a time: a new one replaces the old one. "Grounded" means not Flying-type and without Levitate or Air Balloon.
Pokémon with Grassy Surge (1)
"hidden" means it is that form's hidden ability. Megas have a fixed ability.
Data: Pokémon Showdown (smogon/pokemon-showdown) · commit d601443 · Data & methodology