Nintendo announced the Pokemon’s entry today in a special Direct focused on Super Smash Bros. for Wii U.
According to the announcement, those who purchase both the Wii U and 3DS versions of Super Smash Bros. will be able to download Mewtwo for free for both versions of the game. The character is still currently in development, but downloadable codes are targeted to be released in Spring 2015.
Mewtwo is a notable Pokemon from the early days of the long-running franchise with psychic powers. Nothing about Mewtwo’s move set is yet known, although it is likely that its moves will be centered on psychic abilities.