Letterman: The Last Giant of Late Night by Jason Zinoman:
George Meyer also wrote satire, though he favored nonsense, abstract jokes like the giant doorknob. In one sketch, he wrote a character who would interrupt Letterman, shout about Stupid Pet Tricks being fixed, and then get dragged off the stage. He became known as the Conspiracy Guy and was played by Chris Elliott, then a runner on staff. This sketch set the template for a series of characters played by Elliott in the same vein, including the Guy Under the Seats, the Panicky Guy, and the Fugitive Guy.
In a segment Meyer proposed, two stagehands participated in a contest between a humidifier and a dehumidifier. Letterman called this “the single most brilliant idea on the show ever.”