Comicbook hero Superman has been epitomised in many comics (by DC Comics), movies (starring the late Christopher Reeve), TV shows (eg. Lois and Clarke, Smallville), cartoons (eg. The Adventures of Superman) and even a musical. He and the world he lives in have been referenced many times in Buffy the Vampire Slayer and Angel:

• In Never Kill a Boy on the First Date, Buffy says, “even Clark Kent has a job”, alluding to Superman’s alter-ego.
• In Reptile Boy, Xander’s chances of ever belonging to a fraternity of rich and powerful men are rubbished by Cordy as likely only “in the Bizarro world.” The Bizarro world is a weird, back-to-front version of the real world in Superman.
• In the episode Ted, Cordelia says of Buffy, “But she’s like this Superman.”
• In The Wish, Cordelia says to vamps Willow and Xander, “No. No! No way! I wish us into Bizarro Land, and you guys are still together?! I cannot win!”
• In Helpless, Oz and Xander discuss which colour Kryptonite hurts Superman. Writer David Fury said in his DVD commentary for the episode that he wasn’t sure which Kryptonite was which so wrote this scene as such.
• In The Zeppo, there area few references to Superman: Xander’s line, “But, gee, Mr White, if Clark and Lois get all the good stories I’ll never be a good reporter”, which he acknowledges as a “Jimmy Olsen joke”. He also name-checks the Daily Planet’s editor Perry White, Superman’s alter ego Clark Kent, and his colleague Lois Lane. Cordelia’s jibe “You must feel like Jimmy Olsen” is another reference to the Daily Planet’s youngest photographer.
• In Doomed, Forrest says to Riley, “Granted they’re a little rarer than the one’s you grew up with on that little farm in Smallville.” Smallville, Kansas, was the small town where Clark Kent (Superman) grew up.
• In Superstar, Xander mentions Kryptonite again.
• In Real Me, Xander says, “She can turn this place into the fortress of solitude again”. Superman built the Fortress of Solitude in the North Pole as a place where he could relax and keep his souvenirs.
• In Gone, Andrew mentions Superman’s nemesis Lex Luthor. Buffy also mentions Bizarro World again.
• In Two To Go, Andrew says, “Lex Luthor had a false epidermis escape kit in Superman Versus the Amazing Spider-Man Treasury edition”.
• In Bring on the Night, Andrew says, “An evil name should be something like Lex” He’s referring to Superman’s nemesis Lex Luthor.
• In the Angel episode Blind Date, Wesley says, “The human eye is only capable of registering a small portion of the electromagnetic spectrum. But if Brewer were somehow equipped to see outside that range…” to which Cordelia replies, “She’d be Superman.”
• In You’re Welcome, Cordelia ends her seeming obsession with the Bizarro world when she says, “What Bizarro-world did I wake up in?”