Monsters University — Pixar's upcoming school days prequel to Monster Inc. — isn't out until June 21, 2013, but that hasn't stopped the studio from releasing four slightly different cuts of the first trailer. In order, here are the YouTube, Yahoo, Huffington Post, and iTunes versions of the teaser trailer. John Goodman and Billy Crystal return to voice the lead monstrous duo, and here's the synopsis:

Mike Wazowski and James P. Sullivan are an inseparable pair, but that wasn't always the case. From the moment these two mismatched monsters met they couldn't stand each other. "Monsters University" unlocks the door to how Mike and Sulley overcame their differences and became the best of friends.