Harleen Quinzel, also known as Harley Quinn, was intended to be the secondary antagonist of the cancelled fifth entry in the 1990s Batman franchise, which was going to be titled either Batman Triumphant or Batman Unchained. In this version, she would have been reimagined as the daughter of the Joker from 1980's Batman (instead of his lover) that seeks revenge on Batman for killing her father.
She was intended to be portrayed by either Madonna or Courtney Love.
In the reimagining of the character, Harley Quinn would have been the daughter of the late Jack Napier/Joker instead of his lover, and a toymaker instead of a psychiatrist. Seeking revenge on Batman for killing her father, Harley becomes a supervillain and teams up with Scarecrow to poison Batman with a fear toxin and make him go insane so he can be institutionalized in Arkham Asylum. However, with the help of Robin (intended to be reprised by Chris O'Donnel from Batman Forever and Batman and Robin), Batman would have defeated Scarecrow and Quinn and overcome his fears, and ended the film by standing in a cave with bats swirling around him.
However, due to the incredibly poor reception to Batman and Robin, George Clooney swearing off the role, and Joel Schumacher's reluctance, the project was cancelled. The idea was rewritten by Lee Shapiro and Stephen Wise into a new story called DarKnight that would have also featured the Scarecrow as the main antagonist, but replaced Harley Quinn with Man-Bat as his partner. This was also scrapped.