Meganium

Overgrow : When this Pokémon has 1/3 or less of its HP remaining, its Grass-type moves inflict 1.5× as much regular damage.

Leaf Guard : This Pokémon cannot be given a major status ailment during strong sunlight. This ability does not heal prior status ailments. Rest will fail altogether with this ability in effect. Yawn will immediately fail if used on this Pokémon during strong sunlight, and an already-used Yawn will fail if the weather turns to strong sunlight in the meantime.