Sarazanmai (Ikuhara, Kunihiko)

After accidentally breaking a statue of a kappa, junior high students Kazuki, Toi, and Enta are transformed into kappa themselves as punishment by Keppi, prince of the Kappa Kingdom. Keppi has a task for the boys if they want their bodies back: work for him to hunt down zombie kappas! Can the boys complete their mission—even if it means exposing their own darkest, deepest fears and desires to each other?

(Source: Seven Seas Entertainment)