Everyone that bought and registered Super Smash Bros. for the 3DS and Wii U on Club Nintendo before March 31st have probably been enjoying beating down your opponents with Mewtwo for the last two weeks.
Nintendo sent out Mewtwo codes on April 15th for everyone that bought and registered the game prior to that date. Those that missed out on the opportunity to register both games before that date would only be able to play as Mewtwo by purchasing him as a standalone character.
Today, he becomes available for purchase. If you plan on grabbing Mewtwo, he will cost $3.99 for the 3DS version and $4.99 for the Wii U version. Enjoy!