Gegege no Kitarou (1968) EP9 - Monster to Look Up

A group of boys are riding their bikes. The leader of the group of friends, Chūsuke yells at rest for not being as fit as him, as they are not keeping up with his pace. On their way to his house, Chūsuke notices his friends had stopped behind him. The other kids had discovered a creepy thing in the woods and ponder together on what it could be. Nezumi-Otoko then appears and tells him it's a ghost mailbox that belongs to GeGeGe no Kitarō. As his friends shiver in fear, Chūsuke doesn't believe him and kicks at it. Ignoring Nezumi-Otoko's warnings Chūsuke pulls the mailbox out of the ground, throwing it away. Later in the day after the boys has had their lunch, Chūsuke decide to hike up Mt. Irazu by himself. The farmer that he met earlier told him that the mountain was dangerous, and he wanted to test if the story was true.