"The Impractical Joker"
Joker vandalizes several key-themed stores in Gotham City, and leaves a clue for the Caped Crusaders that points to billionaire Angus Ferguson's priceless key collection. But when they try to stop the theft, Joker uses a small box and key that hypnotizes them instantly, and he walks away with the jewelled key of Kaincardine. The press begin to suggest that they may be powerless to stop his next crime.
We learn that Bruce and Dick regularly watch The Green Hornet.
More body mutilation hijinks with the Joker!