For the Pokémon X & Y release on 3DS, some Pokémon will allow for evolutions into Mega forms. During battle some Pokémon will undergo a transformation that will change a Pokémon for the remainder of a battle. To achieve these Mega forms, players must equip Pokémon with a Mega Stone which will trigger transformation for new abilities.
The gallery below shows three new Pokémon that can achieve these Mega forms. Ampharos, Absol and Mawile will all see Mega forms in X & Y.
The inclusion of a simpler way to EV train (Effort Values) also found its way into the game. Days of killing endless amounts of Special Attack Pokémon will soon end with the new mini-game.
Pokémon X & Y will release on the 3DS October 12th.
Via: Reddit