The Pixar Theory proposes that all Pixar films take place in the same fictional universe and are connected through timeline and characters. The theory was created by Jon Negroni in 2013 and published on his blog, arguing that films like Toy Story, Finding Nemo, The Incredibles, and others share the same world and tell a larger story about humanity. The document provides an overview of the theory and lists the Pixar films it analyzes for connections.