Leafeon GX - SM146

Ability — Breath of the Leaves
If this Pokémon is your Active Pokémon, once during your turn (before your attack), you may heal 50 damage from 1 of your Pokémon that has any Energy attached to it.

Pokémon-GX rule — When your Pokémon-GX is Knocked Out, your opponent takes 2 Prize cards.