For the detail-hungry churn-bucket that is the franchise-film blogosphere, even things that didn’t make it into a movie are big news. And because so many of these projects are drawing from a well-established reservoir of source material, with numerous canons and counter-canons of exploitable characters and storylines, there are always plenty of what-ifs and almosts that get left behind on a whiteboard somewhere.

Case in point, before Zack Snyder and his Batman v Superman cohorts decided to turn their sequel to Man of Steel into a two-hander brawl between two of comics’ biggest names (not to mention a prologue to the Justice League movies), they had spent countless hours percolating ideas for another standalone Superman movie. And since everybody knows that the second comic-book movie is the one that’s really about the villain, that meant they needed a great antagonist to follow in Zod’s city-leveling footprints. “I remember we were talking about, ‘What’s the next ­villain?’ ” Snyder tells EW in this week’s Comic-Con Preview issue. “‘We can’t do another alien invasion.’ Brainiac was definitely down the road. Metallo, I think, was going to be the main bad guy of this movie.”

Obviously, Batman has a whole lot more name recognition going for him than Metallo, who, if you couldn’t tell by the fact that his name is primarily comprised of the word “metal,” is a supervillain who is primarily comprised of metal. The cyborg would have made an interesting choice considering the similar use of a robo-nasty in Avengers: Age of Ultron, but it was not to be. “I said, ‘What about at the end of the movie we do a scene where there’s a crate full of kryptonite delivered to Wayne Manor,’” Snyder says he told fellow DC cinematic godfathers Christoper Nolan and David Goyer. “Everyone was like… ‘Okaay.’ Once you say it out loud it’s a problem because you can’t unsay it.”

Batman v Superman won’t be entirely bereft of representatives from Superman’s rogue gallery, though. In the film, Jesse Eisenberg plays Lex Luthor, the grand-daddy of all Man of Steel villains and one that was always intended to make an appearance. “We did talk about Lex right away,” Snyder says. “I think Lex was always on the books.”

Dive into this week’s issue for even more Comic-Con fare, including an in-the-flesh look at Pride and Prejudice and Zombies, an oral history of M. Night Shyamalan’s Unbreakable, a visit to the set of NBC’s upcoming Heroes: Reborn, and exclusive first-look images from anticipated movies and TV series including The Hunger Games: Mockingjay – Part 2, Fantastic Four, Maze Runner: The Scorch Trials, Fear the Walking Dead, Ash Vs. Evil Dead, and much, much more!