arrive on Earth until after Gordon has established herself as Oracle, and many of the adventures she shared with Batgirl are retroactively described as having been experienced by Power Girl. In Secret Origins (vol. 2) #20 (1987), Barbara Gordon's origin is rebooted by author Barbara Randal. Within the storyline, Gordon recounts the series of events that led to her career as Batgirl, including her first encounter with Batman as a child, studying martial arts under the tutelage of a sensei, memorizing maps and blueprints of the city, excelling in academics to skip grades, and pushing herself to become a star athlete. Batgirl Special #1 and Batman: The Killing Joke (1988) DC officially retired the hero in the one-shot comic Batgirl Special #1 (July 1988), written by Barbara Kesel. Later that year, she appears in Alan Moore's Batman: The Killing Joke. In this graphic novel, the Joker shoots and paralyzes Barbara Gordon in an attempt to drive her father insane, thereby proving to Batman that anyone can lose their minds after having "one bad day". She is deployed as a plot device to cement the Joker's vendetta against Commissioner Gordon and Batman. In 2006, during an interview with Wizard, Moore expressed regret over his treatment of the character, calling it "shallow and ill-conceived". He stated prior to writing the graphic novel, "I asked DC if they had any problem with me crippling Barbara Gordon—who was Batgirl at the time—and if I remember, I spoke to Len Wein, who was our editor on the project", and following a discussion with then-Executive Editorial Director Dick Giordano, "Len got back onto the phone and said, ‘Yeah, okay, cripple the bitch.'" Although there has been speculation as to whether or not editors at DC specifically intended to have the character's paralysis become permanent, Brian Cronin, author of Was Superman A Spy?: And Other Comic Book Legends Revealed (2009) noted that DC had hired Barbara Kesel to write the Batgirl Special specifically to retire the character and set her in place for The Killing Joke. Gail Simone included the character's paralysis in a list of "major female characters that had been killed, mutilated, and depowered", dubbing the phenomenon "Women in Refrigerators" in reference to a 1994 Green Lantern story where the title character discovers his girlfriend's mutilated body in his refrigerator. Following the release of the graphic novel, comic book editor and writer Kim Yale discussed