JoJo no Kimyou na Bouken Part 4: Diamond wa Kudakenai

Synopsis

Josuke and Koichi hear from Tamami that a high school student named Hazamada might also be a Stand user, so the two go to the school and investigate. Josuke checks inside Hazamada's locker, and finds a strange wooden doll inside, but nothing else out of the ordinary. However, as Josuke is inspecting the doll, it suddenly turns into Josuke, and attacks him and Koichi...

(Source: Crunchyroll)