Batman (1966)

S2E21 The Impractical Joker

The Joker orchestrates a series of key-themed pranks across Gotham City, ultimately using his enchanted box to steal a valuable jeweled key right from under Batman and Robin's watch. The Dynamic Duo soon catches on to his antics and manages to stop him during their next showdown. Nevertheless, the Joker is not finished; he devises a sinister plot to eliminate both heroes before executing his grand finale.