Rex Banner is the main antagonist of the 1997 The Simpsons episode Homer vs. the Eighteenth Amendment.
He is a U.S. treasury officer in Washington, D.C. briefly sent to Springfield to uphold Prohibition, and to replace Chief Wiggum as Chief of Police. His main objective was capturing the "Beer Baron", a rum-runner who was actually Homer. When this was finally done by Wiggum, Rex was fired, both from his job as chief, and from the main mechanism of punishment for breaking the ancient prohibition law: catapult. During Trappuccino in The Simpsons Movie released 10 years later, he was also seen as part of the angry mob that seeks to kill Homer, indicating that Rex has survived the catapult.
- Rex Banner was based on Eliot Ness, the Treasury agent who led the famous Prohibition-enforcement team "The Untouchables".
- His voice is based on Robert Stack's portrayal of Ness in the Untouchables TV series.
- His appearance is based on Kevin Costner's portrayal of Ness in the Untouchables film.