In a flashback, it shows Thomas and Martha Wayne being confronted by an unidentified mugger, just after watching a Robin Hood movie with their small son Bruce. When Thomas ends up trying to fight the mugger, Bruce quotes "No Dad, he's got a..." and lightning is shown in the sky as his parents are shot. The episode was written by Alan Burnett, later a story editor on "". This was also a lengthy appearance of Bruce Wayne and Dick Grayson outside their Batman and Robin persona. This series also marked the first ever appearance of Cyborg in an animated television series. Cyborg's origin was told via a medical journal read by Dr. Martin Stein saying Cyborg was a promising decathlon athlete until an accident destroyed most of his body and his father replaced part of his body with machine parts. Also, he is not a Titan. He becomes fast friends with teammate Firestorm. He is an affiliate of the Justice League of America under Superman. In the introductory episode to Cyborg, "The Seeds of Doom", Cyborg's abilities save Earth from Darkseid's seeds, but as Superman warns, makes Darkseid a dangerous enemy to Cyborg, so Cyborg joins the League. The Flash appeared only in "The Death of Superman" episode #7, and never used his powers. El Dorado, even if he was not part of the official roster, also made a cameo in "The Death of Superman", and never used his powers or even spoke any lines. Also "The Death of Superman", the Fortress of Solitude more closely resembles the pre-"Crisis" comic-book version, including a giant yellow key whose use required the combined efforts of Green Lantern, Wonder Woman and Cyborg. This was the first time Wonder Woman's red boots were animated with white stripes since the cancellation of Lynda Carter's live action television series on CBS six years earlier. Boom tubes were used here, but referred to as "Star Gates," and they are used by the natives of Apokolips, though without the sonic boom caused by boom tubes; these were carried over from the previous season. New Genesis was never shown or mentioned. Both The Joker and The Penguin made their first (and only) "Super Friends" appearances in two different episodes. While Batman and Robin appeared in Joker's debut episode, they were not present in Penguin's. In addition, the episodes "The Death of Superman" and "The Seeds of Doom" were included on Warner's 25 Cartoon Collection: DC Comics, released on August 27, 2013. The episodes "The Seeds of Doom" and "The Death of Superman" were included on disc 2 of Warner's The Best of Superman, released on June 4, 2013.