heliolisk

Causes 1/8 max HP in damage each turn during strong sunlight, but heals for 1/8 max HP during rain. Increases damage from Fire moves to 1.25×, but absorbs Water moves, healing for 1/4 max HP.

“Restores the Pokémon's HP in rain or when it is hit by Water-type moves. Reduces HP in harsh sunlight, and increases the damage received from Fire-type moves.”

Increases evasion to 1.25× during a sandstorm. Protects against sandstorm damage.

“Boosts the Pokémon's evasiveness in a sandstorm.”

Increases Special Attack to 1.5× but costs 1/8 max HP after each turn during strong sunlight.

“In harsh sunlight, the Pokémon's Sp. Atk stat is boosted, but its HP decreases every turn.”