Mario.EXE is the main antagonist of the mod. He originates from an art piece on DeviantArt made by Shadow-Shana, with the name Super Horror Mario, which is commonly used for YouTube thumbnails about Mario creepypasta games. In Mario's Madness, Horror Mario, now known as Mario.EXE, is a demonic entity that resides inside a cursed cartridge and ends up in the possession of Boyfriend and Girlfriend, who are drawn into his world of madness to revel in his suffering. He is the opponent of Its-a Me