High Quality Content by WIKIPEDIA articles! Beginning with Red`s Dream and its references to previous Pixar short films, Pixar has included references in its films to other works produced by the studio. These have included cameo appearances, references to characters, objects, and titles of works. Additionally, such easter eggs or in-jokes can refer to Pixar staff, associates, or places or events from the company`s past. Lastly, some items, such as A113, Pizza Planet or actor John Ratzenberger have appeared in the majority of Pixar films, establishing a set of traditions that subsequent Pixar films try to include.