"The Contaminated Cowl"
Mad Hatter's henchmen beat up Batman and Robin and herd them into an 'X-ray generator tube and fluoroscopic cabinet'. He then bombards them with high voltage x-rays.
"First Batman's cowl radio-activated!! And now the caped crusaders fluoroscoped forever??"
Batman's bat x-ray deflector protects them from the deadly radiation, until atomic energy expert Dr. Overbeck releases them from the cabinet. Batman cunningly places extra costumes from the Batmobile on two skeletons, causing the cleaning lady to think they are deceased, which leads to a state of world-wide mourning.
Mad Hatter and the rest of the world are convinced that he has killed Batman.