“South Park” creators Matt Stone and Trey Parker gave some New York University undergrads quite a shock when they crashed their writing class.

The Tony winners didn’t do this on the whim. They were participating in the MtvU series, “Stand In,” which replaces college professors with famous people. Past teachers for a day include John Legend and Annie Lennox.

In the clip, Park and Stone explain how they use a whiteboard and colored markers to lay out a cohesive episode of their Comedy Central show. I assume NYU’s campus store sold out of both as soon as class was dismissed.

Watch the preview, which doesn’t contain any NSFW words but it bleep heavy, below.

(Via The Daily What)