Mega Evolution is a special transformation that certain Pokémon can undergo during battles. This process allows them to temporarily evolve into a more powerful form, enhancing their abilities, stats, and sometimes even changing their type. To initiate Mega Evolution, a Pokémon must hold a specific item called a Mega Stone and the trainer must use a Mega Ring. The transformation lasts only for the duration of the battle, after which the Pokémon reverts to its original form. Not all Pokémon can Mega Evolve; only select species have this capability, making it a unique feature in the Pokémon games and series.