If held by a Lopunny, allows it to Mega Evolve into Mega Lopunny if its Trainer has a Key Stone. Each Trainer can only Mega Evolve one Pokémon per battle.
Unaffected by item negating effects (such as Embargo and Klutz). Item manipulating effects (such as Trick and Fling) cannot give Lopunny a Lopunnite or remove a Lopunnite from Lopunny.
Outside of battle
If held by a Lopunny, allows it to Mega Evolve into Mega Lopunny when it performs a Spectacular Talent during a Pokémon Contest Spectacular while its Trainer has a Key Stone. Lopunny will remain a Mega Lopunny until the Talent Round ends.
