After young Disney animator John Lasseter saw footage of computer animation that an outside production company had created for Tron, Lasseter and colleague Glen Keane won approval to create a short test film incorporating computer animation.
The resulting 1983 film, known as the Wild Things test, was meant to be a sample of a proposed feature film of Where the Wild Things Are. The test combined computer-animated backgrounds with cel-animated characters.
Cartoon Brew has just posted a neat contemporaneous account of the project that appeared in an internal Disney publication (originally posted in December by Hans Perk). I was glad to see Tom Wilhite recognized for his role in the project (he was the Disney live-action executive who approved it—the animation side of the studio wasn’t interested).