Part of a series of animated short films shown at the Ghibli Museum in Mitaka called "Film Guru Guru" . A short film of a fire demon called "Bobo-kun," eating one piece of coal after another. This character would later be re-used as Calcifer, who appears in Howl's Moving Castle.
Watch Bobo-kun online — subbed and dubbed, with automatic AniList / MyAnimeList progress sync.