BATMAN 66 #25
1ST Appearance of Harley in the Batman 66 TV Universe.
Driven mad by the Clown Prince of Crime's "Joker Wave," The Joker's former prison doctor enters the Caped Crusader's Rogues Gallery as The Harlequin! Then, a team of Batman's greatest enemies takes over an advertising agency to create a new public image for themselves. But the agency has a new temp working for them...none other than Barbara Gordon, young daughter of Gotham City's police commissioner!