Junichi Masuda appeared on
Pokémon Smash 50 to announce details about the Mewtwo event revealed by Shoko-tan on
Pokémon Smash 49. The event distribution will take place from
September 26th, 2011 until October 31st, 2011 on the Japanese Nintendo Wi-Fi Connection for players of the Japanese versions of Pocket Monsters Black & White. This Mewtwo has PokéSma! (ポケスマ!) as its OT, has the Pressure Ability, has a Premier Ribbon, comes in a Premier Ball, is holding the King's Rock item and knows the moves
Psystrike,
Shadow Ball and
Aura Sphere. Mewtwo's fourth move was revealed by Shoko-tan on
Pokémon Smash #51 which aired on September 25th, 2011. The fourth move is:
Electro Ball, a move Mewtwo normally cannot learn.
Source:
http://www.pokemon.co.jp/ex/mewtwo/feature/index.html#feat02