During the third-annual D23 Expo, held at the Anaheim Convention Center in California, event host and Disney's chief creative officer John Lasseter debuted a brand-new 'Monsters University' short film, 'Party Central,' which will make its theatrical premiere in front of the upcoming Pixar film 'The Good Dinosaur.'

Directed by Kelsey Man, ‘Party Central’ shows Mike and Sulley helping out the freshman fraternity, OK, to throw the biggest party on campus. Too bad the frat across the street is throwing it already. "We’re not just gonna throw the biggest party of the year,” said Sulley. “We’re gonna steal it,” said Mike. So the team proceeds to use the doorways to steal the party supplies -- and guests -- from the party next door.

“We’re so proud of 'Monsters University,'” said Lasseter. “But there’s one character that surprised us, like we didn’t expect it, that became a bonafide superstar from ‘Monster’s University’ -- the Slug.” That was Bill Hader's cue to come out onstage to re-screen the post-credits scene of 'Monsters University.'

"I’m a huge fan of this place,” said Hader. “Just standing next to you [Lasseter] is an honor.” The actor, who voiced the Slug, is definitely a Disney favorite; he'll be starring as the lead in 'The Good Dinosaur' in addition to a principle role in Peter Doctor's 'Inside Out,' both of which are Disney properties.

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