Unburdenin Pokémon Polished Crystal

Unburden is an ability that doubles the Speed stat of the Pokémon when it consumes its held item. This means that if a Pokémon with Unburden uses a move that causes it to lose its held item, such as Knock Off, its Speed will be doubled for the remainder of the battle. This ability can provide a significant advantage in battles, allowing the Pokémon to outspeed many opponents and potentially strike first.