Ushiro no Hyakutarou
心霊恐怖レポート うしろの百太郎
Horror OVA based on the manga by Jirou Tsunoda. The title roughly means "Hyakutarou behind".
A boy named Ichitarou Ushiro deals with various horrifying phenomena with the help of his guardian spirit Hyakutarou.
2 episodes: "Kokkuri Satsujin Jiken", "Yuutai Ridatsu".
(Source: AniDB)