Captain America 3 wasn’t always going to be “Civil War”. It was contingent on getting Robert Downey Jr. to sign on to a Marvel film that wasn’t an Iron Man or an Avengers picture. Since Marvel was going to make a third Captain America regardless of whether or not Downey came on, the Russos were left with ideas for what Cap should face in his next solo picture, and they came up with a zombie film.
Speaking to EW, the Russos explained the “Madbomb” from the comics and how they wanted to use it for the climax of the film:
“There was a period where we did discuss a third act that revolved around the Madbomb from Cap mythology. It didn’t have anything to do with ‘Civil War,’ and if we couldn’t get Downey — in the very, very early conversations before we nailed him — somebody pitched the idea of a third-act that revolved around the Madbomb, which makes people crazy. It almost like zombifies them — but not literally.”
If that sounds familiar, that’s because of Agent Carter, the Marvel series that used the idea in its first season (coincidentally, that’s also the villain’s plan in Kingsman).
The Russos liked the idea of the Madbomb because it would force Captain America the people he had sworn to protect.
“The notion of the Madbomb would have been Cap having to fight civilians and how he would he handle that,” Joe Russo said. “We were always trying to put him into these interesting moral conundrums because of his nature. That would have made a compelling third act because if civilians are the antagonists, how could he stop them without killing them?”
“Somebody you know has turned into a zombie and now you have to fight them. And there would have been the emotional component of that,” Anthony Russo added.
Nonetheless, when Cap fights Iron Man in Civil War, it’s because Tony Stark, although filled with rage and anger, is still making a conscious decision, and that’s far more rewarding for the audience.
Captain America: Civil War hits Digital HD, Digital 3D and Disney Movies Anywhere on September 2nd and Blu-ray 3D, Blu-ray, DVD and On-Demand on September 13th.