Romaji: Kaizō Mario Wārudo) is a ROM hack of Super Mario World created by T. Takemoto. The original title of Kaizo Mario World was "Making my friend play through my Mario hack (Super Mario World)"(JPJapanese: 自作の改造マリオ（スーパーマリオワールド）を友人にプレイさせる
Romaji: Jisaku no Kaizō Mario (Sūpā Mario Wārudo) o Yūjin ni Purei sa Seru), as it was created by Takemoto for his friend R. Kiba.
The hack is notable for deliberately breaking all normal rules of "good practice" level design, and introduced many staples of later Kaizo Hacks, such as hidden blocks, extremely fast autoscrollers, dying after the goal post and various other traps.
The ROM hack first game gained popularity after being uploaded on YouTube under the title Asshole Mario.