"The battle had all sorts of stuff in it. I don't know how long that battle is now, but it's not as long as you might think," co-writer Stephen McFeely told Backstory Magazine.
"I know a lot of people were saying they can't wait for [Hulk and Thanos'] rematch. Well, that would've made sense had he not become Smart Hulk. He's a whole different thing, and that's not what drives him. So we never thought, 'Oh, he really is trying to get a crack at Thanos now.'"
Smart Hulk, the successful amalgamation of Banner's brain and the Other Guy's brawn, was once planned to debut in the Wakanda-set climax of Avengers: Infinity War after Hulk spent much of that film's runtime retreated in Banner after being handily defeated by Thanos aboard the Statesman.
McFeely and co-writer Christopher Markus decided Smart Hulk emerging minutes before the Avengers suffer their devastating defeat would have been "completely the wrong tone for that moment in the movie," Markus explained at San Diego Comic-Con.
"It was this victory when we were headed toward a crushing defeat, and it was tone deaf," Markus added. "But we had already shot Endgame, where he was already Smart Hulk."
"Imagine the first act of Endgame, he's Smart Hulk in all of those scenes — meaning when he goes to kill Thanos, when they're sitting around the compound when Tony's returned — so that required some adjusting," said McFeely.
"And it also meant that we could use the five years as the transition, hint that he's got problems coalescing, and in the five years he figures it out. You have a couple of lines about gamma radiation and he's eating pancakes, and off you go."
A time-saving scene of Smart Hulk explaining his new form over pancakes ultimately made the final cut over a deleted scene showing the new Hulk rescue civilians from a burning building.
"A really funny scene where Hulk is eating pancakes is fast, it's funny, it makes you really happy, and it is a scene I haven't seen in a superhero movie before," Markus said. "Let's accept that challenge and try to push the whole thing forward, push the genre forward."
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