Batman TAS: Mad Love. (the Harley Quinn origin story)

Harley reflects on what led to her partnering with the Clown Prince of Crime, the Joker.
The comic book that this episode was adapted from was originally released in 1994 as a special issue of The Batman Adventures based on the show Batman: The Animated Series. It won the Eisner Award for “Best Single Story.”

Poison Ivy is seen in Arkham Asylum during the flashback to Harley Quinn’s origins, meaning that this episode takes place at least after Poison Ivy’s premiere episode, “Pretty Poison”. This episode takes place with the designs of Batman and the Joker from Batman Gotham Knights in Harley’s flashback of how she became Harley Quinn. But at that time she was in Batman: The Animated Series which had different designs for them.

Allusions:

Joker: May the Floss be with you. This is a direct allusion to the movie Star Wars, even more so because it was Mark Hamill, voicing the Joker, who said it as Luke Skywalker.
Title: While there have been several movies by this name, the title almost certainly alludes to the most famous – the 1935 movie starring Peter Lorre as an insane doctor obsessed with a beautiful woman who replaces her mutilated hands with those of a knife murderer.