Lex Luthor is arguably the second most iconic villain DC has on its roster. Since being introduced in pages of Action Comics No. 23 in 1940, the villain has had numerous cinematic appearances. Between Gene Hackman's portrayal in the Christopher Reeve Superman films, Kevin Spacey's outing in Superman Returns and Jesse Eisenberg's modernized take in Batman v. Superman: Dawn of Justice, the character is a household name and can carry his own film apart from the Man of Steel.

Phillips had a specific strategy for Joker. He paired an A-list actor with a strong script. He drew upon the films of Martin Scorsese rather than relying heavily on comics. Character overtook story. Performances outplayed spectacle. A Lex Luthor film could use the same formula for success. Fans in the past have called on Bryan Cranston or Mark Strong to play the part, and both would be solid choices. But Joker worked because Joaquin Phoenix felt out-of-the-box. Personally speaking, someone in the realm of Michael Fassbender or Mahershala Ali would be standout choices for a potential film.

As for its cinematic influences, perhaps Phillips could draw from Scorsese's The Wolf of Wall Street or David Fincher's The Social Network, a film that may have inspired Eisenberg's casting as Luthor in Batman v. Superman. The modern billionaire comes in the shades of Mark Zuckerberg, Jeff Bezos and Elon Musk more than the classic comic book Luthor, so that could be a signpost for a movie.

While Joker prided itself on not following any singular comic book storyline, it did include visual references and thematic nods to stories like The Killing Joke and The Dark Knight Returns. For Lex Luthor, there are plenty of stories and visual cues to mine. The primary one could be 2015's Lex Luthor: Man of Steel by author Brian Azzarello and artist Lee Bermejo. The story is a deep dive into Luthor's psychology, providing a definitive "why" to his character. In the story, Superman is used as a mythological boogeyman, primarily appearing behind long glass mirrors or manifesting in Lex Luthor's mind as he obsesses over the Kryptonian hero. Having Superman appear in a Lex Luthor film through shadows, silhouettes or conceptual images would be a way to use the character as a phantom antagonist to Lex, his primary motivator. The key to Lex Luthor is that he never sees himself as the villain; rather, he sees himself as the savior of humanity. To him, Superman is everything humanity isn't. Superman is overly powerful, overbearing. A mockery to Lex Luthor's own hard-fought journey to the top.

While most superhero pics are made with escapism as the primary audience goal, Joker, and other darker films in the medium, aimed to point a mirror at our world rather than take us away from it. It was debatable whether audiences were ready for such an exploration using comic book characters, but Joker proved it could work. Where Joker took stabs at wealth inequality and mental health services, a Lex Luthor film could get even more political, and even tackle themes of religion and humanity's place in the universe to make it the opposite side of the DC villain coin.