Mysterious Mose is a 1930 American animated short film directed by Dave Fleischer, produced by Fleischer Studios and released through Paramount Pictures as part of the Talkartoons series.
The film contains an early version of Betty Boop and the studio's star, Bimbo. "Mysterious Mose" is also the name of a popular song from 1930 (which is sung in the short).

Synopsis
Betty is startled awake in her bed on a stormy night. She searches for the cause of the shock while she sings the song. Then, unexplainable phenomena start happening in the house. Mysterious Mose (Bimbo) appears, and sings part of the song. Bizarre cartoon creatures appear and, at first, sing and enhance Mose's "mysterious" image. Quickly, however, the antics become frightful even to Mose. The film escalates into chaos, which ends when Mose bursts, revealing him having been an automaton (full of cogs and springs) the whole time.