Sredni Vashtar.

Sredni Vashtar is a 1981 short film, written, produced and directed by Andrew Birkin, based on the short story of the same name written by Hector Hugh Munro. The story concerns a slowly dying ten-year-old boy named Conradin, who lives with his strict cousin and guardian, Mrs. De Ropp. Conradin rebels against her and invents a new religion for himself, which centres on idolising a polecat-ferret he calls Sredni Vashtar; a vengeful, merciless god. The film won the BAFTA award for Best Short Film, and was nominated for an Academy Award for Best Live Action Short Film.