Juxtaposing live action with animation is nearly as old as film animation itself. Emile Cohl and Winsor McCay interweaved live-action narratives about the animator with the animated cartoon. The next step was taken by John Randolph Bray, Walt Disney with his Alice's Wonderland series and the Fleischer Brothers, among others; they created films where the real, live-action world and the cartoon world interact. This particular Fleischer Brothers short, part of their Out of the Inkwell series, is notable for its play on the notion of creators and creations and for an exceptionally well executed version of the battle between creator and creation that usually occurred in the series.
"The Cartoon Factory" begins, as usual in the series, with Max Fleischer drawing Koko the Clown, who instantly comes to life. Max arbitrarily torments his creation for a while, but then Koko happens upon a drawing machine and shop--a cartoon factory--within the cartoon world, all of which can create live-action within the cartoon world (sometimes merely still photographs). In the Out of Inkwell series, it was the cartoon that usually entered the real universe. But no, here, Koko, who was originally modeled on Max (via Max's invention, the rotoscope, which was abandoned for a more cartoony Koko this episode), eventually creates a toy soldier, which comes to life as the live-action Max. Max sets about drawing subordinate toy soldiers, whom he orders to attack Koko.
This animation short features an especially clever exploration of the interactions between the universe of the creator and that of the creation. Koko the Clown was the Fleisher's first popular character, who in his later incarnations was often accompanied by Fitz the Dog, such as in the very inventive, apocalyptic "Ko-Ko's Earth Control" (1928). Koko isn't as well remembered as the Fleisher's later creations Betty Boop and Popeye, but with Felix the Cat and Mickey Mouse, he was one of the first popular and sustained cartoon characters in film history. The interaction between creators and creations, however, were the lasting importance of the Out of the Inkwell series featuring Koko.