JEFF WINGER IS ON THE HOT SEAT WHEN IT APPEARS HE HAS FABRICATED A CLASS FOR CREDIT -- KEVIN CORRIGAN GUEST STARS -- When Dean Pelton (Jim Rash) begins checking class schedules, he discovers that Jeff (Joel McHale) has listed a class that doesn't exist. Just when it appears Jeff will be caught in a lie, the mysterious "Professor Professorson" (Kevin Corrigan "The Departed") emerges from the shadows to confirm that Jeff has been taking his class, "Conspiracy Theories in U.S. History," at night school. When Jeff later admits to Annie (Alison Brie) that he's never seen Professor Professorson in his life, the two decide to find out who the professor really is. Meanwhile, Abed (Danny Pudi) and Troy (Donald Glover) are busy building the most elaborate blanket fort that Greendale Community College has ever seen. Chevy Chase, Gillian Jacobs, Yvette Nicole Brown and Ken Jeong also star.