Sisyphus is a character appearing exclusively in the MegaDrive/Genesis version of Teenage Mutant Ninja Turtles: Tournament Fighters. No back story is given to him, although he is indicated to be a friend of the Ninja Turtles. Sisyphus is a mutant scarab.
Sisyphus is likely named after the species of dung beetle (aka scarab) of the same name. Scarabs are known for rolling large balls of feces and other material, similar to the punishment given to the Greek myth character of Sisyphus.
In the Japanese version of the game, he is known as Musha Beetle. Musha is Japanese for "warrior", and it's likely also a pun on "mushi" (bug/insect) since the kana reads "むしゃ".
- ↑ タートルズの仲間でカブトムシのミュータント。, Japanese manual for Tournament Fighters.