23. "Nightmare Cafeteria" (Treehouse Of Horror V, 1994)
In this segment, the Springfield Elementary School detention room has become dangerously overcrowded, while the cafeteria budget has been slashed to the point where "Grade F" meat is actually a luxury. So to solve their mutual problem, Principal Skinner presents a fiendish idea to Lunchlady Doris. Soon, Bart, Lisa, and Millhouse are eating “Sloppy Jimbos” and enjoying a heaping helping of “Üterbraten” at lunch, while their friends Jimbo and Üter have mysteriously gone missing after being placed in detention.
This is one of the more twisted Halloween specials that the show has ever come up with. Between the copious amount of bloodshed and the mere thought of a cannibalistic student body, it can be argued that 'Nightmare Cafeteria" is as close to true horror as the Simpsons has ever gotten.