The plus button is a small round button on the Wii Remote, Classic Controller, Wii U Gamepad, and Wii U Pro Controller. It is equivalent to the start button on the Nintendo 64 Controller and the Gamecube Controller. Its primary use is for pausing during offline matches. In Online matches, it brings up a menu asking if you want to leave the match. It is commonly used for transitioning from the character selection screen to the stage selection screen once the players have chosen their characters.