Cryogenist

He's the drowsy, half-attentive night clerk at Applied Cryogenics on New Year's Eve, 1999, more interested in getting home than in doing his job properly. He putters through his closing routine, oblivious to the pizza delivery boy who's about to tumble into one of his tubes.

He's barely five minutes of screen time, but Maurice LaMarche gives him a perfect deadpan slackness — the voice of a man who has stopped caring about anything except leaving on time. That indifference is the entire joke: the most consequential accident in the show's history hinges on someone too bored to notice.