Osomatsu-kun: Hachamecha Gekijō (おそ松くん はちゃめちゃ劇場, “Nonsense Theater”) is a platform video game by Sega, which was released in 1988 for the Sega Mega Drive. One of four launch titles for the Mega Drive, it is the only one to not see a release outside of Japan. The game was based on the manga Osomatsu-kun by Fujio Akatsuka, and acts as a promotion for the anime adaptation that premiered the same year; players controlled the title character and encountered many of the series’ characters in a strange (but comical) world.