Students enrolled in the New York University’s freshman level Storytelling Strategies course got quite a thrill when ‘South Park’ creators Trey Parker and Matt Stone showed up during their first class of the semester as surprise guest lectures.

It’s part of the mtvU series ‘Stand In,’ in which celebrities teach college classes. The Matt and Trey episode will air on October 3, but a preview clip released today shows the comedy duo engaging with their pupils:

[via BuzzFeed]