Many people have claimed that Leslie Nielsen's first comedic role was the bumbling Doctor Rumack in the comedy classic Airplane! However, he actually played a comedic role seven years before- in the first season of M*A*S*H.
Leslie played the reckless Colonel Brighton, referred to as the ringbanger by Hawkeye due to his habit of impatiently banging his ring on the arm of a chair. Mr. Nielsen's character recklessly sacrifices the troops under his command for minimal gains, a situation that the guys try to rectify by getting the Colonel sent back to the states. Through an elaborate scheme that nearly backfires, the guys accomplish just that. We never see this "ringbanger" again.
