Wart, also known as King Wart and in Japan as Mamu (Japanese: マムー Hepburn: Mamū), is a fictional character from Nintendo. He is an anthropomorphic frog king who debuted as the main antagonist and final boss of two Nintendo games: 1987's Yume Kōjō: Doki Doki Panic for Famicom in Japan, and 1988's Super Mario Bros. 2 for NES outside Japan. Wart is the leader of a militaristic dictatorship, known as the 8 bits or the 8 bit Club. He is an evil nemesis of Mario, Luigi, Toad, and Princess Toadstool.
Wart made his debut appearance in 1987's Yume Kōjō: Doki Doki Panic, where he plays a role of a main villain and final boss of the game. The game was converted into 1988's Super Mario Bros. 2 for its North American release. While some characters and music were changed into Mario series elements and the game world is named Subcon, Wart remains as the game's antagonist, instead of Bowser, who usually serves that role in the series. In both versions, Wart creates his own monsters with a device known as the "dream machine", appoints himself ruler of the land, and enslaves its inhabitants. However, Wart is ultimately to be defeated by the protagonists and then castigated severely by the liberated populace.