Created by the Fleischer brothers, the role of an "in-betweener" was to fill in the intermediate action between two drawings created by a lead animator. This job required that the artist be able to reproduce the lead animator's style (often the house style). The commercial animation industry required that different artists be able to draw in a consistent, coherent style. This fundamental convention became so established that it was later mocked in cartoons such as Duck Amuck (1953), which disrupts the enclosure of the animated world by self-reflexively breaking the fourth wall, having Daffy entreat the audience to save him from a sadistic animator, who turns out to be fellow character Bugs Bunny.