Duck Amuck (1953)

Daffy Duck plays a Musketeer, but as he advances on his enemy, the background disappears; Daffy demands the proper scenery, and an animator paints a completely inappropriate background - the start of a running duel between Daffy and the unseen animator who changes backgrounds, Daffy's appearance, the soundtrack, and even the film projection under Daffy's feet, forcing the mad mallard to improvise his performance and leaving him screaming for the animator's head.