Synopsis: Bimbo’s Initiation is a 1931 Fleischer Studios animated short film starring Bimbo and featuring an early version of Betty Boop with a dog’s ears and nose. It was the final Betty Boop cartoon to be animated by the character’s co-creator, Grim Natwick. Bimbo is walking down the street when he suddenly disappears down an open manhole and is subsequently locked down there by a mouse who resembles Mickey Mouse.