Summer Days with Coo (2007)

In contemporary Japan, a solitary Kappa named Coo has astonishingly endured for over 200 years. Young Koichi discovers him and, after a heartwarming adoption by Koichi’s family, they embark on a quest together. Determined to locate hidden, uninhabited areas, they hope to uncover any remnants of Coo's kind. Their journey unfolds as a touching exploration of friendship and the search for belonging, bridging the gap between human and mythical worlds.