S3·E2 Abra Cadaver

Carl and Marty are siblings who work at a hospital. Carl shows Marty his new way of proving that the brain lives after the body dies. The whole thing turns out to be a prank but the shock of the joke gives Marty a heart attack. Years later Marty hasn't forgiven Carl and plans a deadly revenge. Marty then reveals that it was an act of revenge on Carl and the whole thing was a joke ... or was it?