Mike and Sully are back together again for the first time in Monsters University — Pixar's prequel to 2001's Monsters, Inc.

Set ten years before the events of the original film, Monsters University "unlocks the door to how Mike and Sulley overcame their differences and became the best of friends."

John Goodman, Billy Crystal, and Steve Buscemi are set to reprise their roles as James P. Sullivan, Mike Wazowski, and Sully's rival Randall Boggs, respectively.

To whet appetites for this highly anticipated release, Disney has released not one, not two, but four slightly different teaser trailers simultaneously. Watch one above, and the rest below.

Opens everywhere June 21, 2013.

[videos via YouTube, Apple, Yahoo, HuffPo via ComingSoon]