Going back in school is never easy, but Mike and Sully -- the lovable creatures from Pixar's 2001 hit "Monsters Inc." -- are about to find out why.

The upcoming prequel "Monsters University" is turning back the clock and checking in on the duo (voiced by Billy Crystal and John Goodman) when they first started college, where they meet as rivals pledging the same fraternity and studying in the same major.

The trailer features furry, slimy spins on typical college-related humor: "Animal House"-style frat hijinks, bad cafeteria food, intimidating co-eds, pompous faculty (including Helen Mirren as the icy headmistress), and jokes about slugs. It's all set to the strains of such noted fixtures of higher education as Motley Crue and Andrew W.K.

Watch the trailer here:




The voice cast also includes Steve Buscemi, Franz OzDave Foley, Charlie Day, Nathan Fillion, Bobby Moynihan, Julia Sweeney, Aubrey Plaza, John Krasinski, Bonnie Hunt, and, naturally, John Ratzenberger.

"Monsters" marks the directorial debut of Pixar vet Dan Scanlon, who co-directed the "Cars"-related short film "Mater and the Ghostlight."

It's part of Pixar's rather recent swing into familiar territories. Besides the "Toy Story" sequels, the animation innovators seemed hesitant to the idea of franchising their hit films until "Cars 2" came along, followed by "Monsters University" and the upcoming "Finding Dory." However, the forthcoming "Cars" spin-off "Planes" doesn't really count, since it's being produced by DisneyToon Studios. 

"Monsters University" opens June 21.

What do you think of the trailer? Are you excited to reunite with the "Monsters Inc." crew? Or would you prefer Pixar to focus more on new ideas?