Once Captain America: Civil War lined up Robert Downey, Jr. as the co-lead of the film, it was inevitable that the movie’s finale would revolve around an intensely personal battle between Chris Evan‘s Cap and Downey’s Iron Man. But what if Downey and Marvel Studios hadn’t come to a deal?

While speaking with Entertainment Weekly, Civil War directors Anthony and Joe Russo acknowledged that there was a contingency plan in place for a conclusion that didn’t revolve around an Iron Man vs. Cap fight. Instead, the Russo brothers would have used a “Madbomb” as the catalyst for the film’s third act, which would have still forced Cap to fight some of his allies. But mainly it would have transformed innocent people into a nearly unstoppable horde, and given Cap the dilemma of trying to subdue them without seriously hurting innocent civilians or his friends.

The Madbomb dates back to Jack Kirby‘s run on Captain America in 1976, which featured a secret society conspiring to use the device to turn Americans against each other before seizing control of the nation for themselves. The victims of the Madbombs may have been out of their minds with rage, but they weren’t considered to be zombies because they weren’t actually dead. However, Cap and Falcon still had their hands full while trying to stop them.

Madbombs have also popped up in later Captain America storylines, but within the Civil War film, the Madbomb would have been Zemo’s final gambit in the script without Iron Man.

“The charm of the Madbomb is that you turn hordes of people into berserkers,” said Anthony Russo. “That was the physical challenge that Cap and company would have had to face.” Russo also touched on some of Cap’s allies being affected by the Madbomb. “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.” Given Cap’s emotional ties to Bucky and Falcon, it seems likely that he would have to fight one or both of them in that scenario.

However, once Downey was officially onboard, the Madbomb ending was abandoned. Ultimately, that made Civil War a stronger story, but perhaps the Madbomb will resurface in the MCU for a future Cap film. Although the Russos confirmed that Steve Rogers abandoned the Captain America identity at the end of the Civil War, anyone who thinks there won’t be any more Cap movies is probably mistaken. Even if its one of Cap’s friends who takes over the role, there will almost certainly be more Captain America films in the future.

Would you have liked to have seen Cap and his team take Madbomb-infected citizens on the big screen? Connect your Kirby dots and share your thoughts below!

Images: Marvel Studios/Marvel