While pioneer animator Ub Iwerks has often been praised as a driving force behind the early success of the Walt Disney Company, his independent work has received scant attention. That relative omission from animation history seems curious given two key features of his cartoon work: an emphasis on gags involving protean, transformative effects – a characteristic often linked to avant-garde filmmaking; and his pioneering work on a multiplane camera – a device that would become crucial to a developing realist aesthetic in American animation. This article examines these features to situate his work in terms of American animation's shifting aesthetic in the 1930s. It suggests that we see Iwerks' cartoons as symptomatic of a larger struggle in this period between the avant-garde and an emerging realism, closely linked to the classical narrative mode of live-action cinema, and the relative failure of his films as indicative of an inability to negotiate between these different pulls.