Super Mario Bros. X is a freeware fan game based the Mario games for the NES and SNES, as well as Metroid and Zelda II: The Adventure of Link. The game's included world contains over 50 main levels and multiple bonus levels, and the game includes a level editor. SMBX introduces items and powerups new to the series, such as propeller blocks, the Billy gun(That shoots Bullet Bills), and Toothy, a wieldable piranha plant. SMBX was written by Redigit, who also developed Terraria. Due to Nintendo's takedown request, Redigit no longer distributes Super Mario Bros. X.