Smart Hulk Was Supposed To Appear First In Avengers: Infinity War
If things had gone differently, Marvel fans would have met the mild-mannered, bespectacled Hulk an entire year early.
During Marvel Studios' panel at San Diego Comic-Con 2019, screenwriters Christopher Markus and Stephen McFeely revealed that Mark Ruffalo's Bruce Banner was meant to merge with his mean, green alter ego the Hulk to become Professor Hulk in Avengers: Infinity War rather than in Avengers: Endgame, where audiences actually met him.
Per Polygon, Markus and McFeely, who wrote both Infinity War and Endgame, explained that one of the most difficult things to get right was crafting Banner's big character moment where he finally settles his differences with the Jade Giant, brings together his brain with the Hulk's brawn, and arises as Professor Hulk. The duo wanted the character's arc to make sense, with viewers easily understanding the motivations behind and the methods of Banner's metamorphosis into Professor Hulk, but it turned out to be more complicated than they initially thought.
Originally, Professor Hulk — also known as "Smart Hulk" — was supposed to made his MCU debut in the third act of Avengers: Infinity War. As Markus explained, the Infinity War team wrote and filmed the whole thing, and it was supposed to be all sorts of awesome.
"He achieved union with the Hulk while inside the Hulkbuster. He kicked Cull Obsidian's a**," he said.
Watching Banner and Hulk become one while wearing the Hulkbuster suit during the blowout final battle of Avengers: Infinity War would have been grade-A incredible, and the film's creative crew apparently agreed. Thus, they swiftly moved along to shoot Avengers: Endgame, thinking everything was ship-shape and would be satisfying for fans.
At some point, though, Markus and McFeely found flaws in their plan to introduce Smart Hulk in Avengers: Infinity War. In their eyes, the magic of the Hulk-Banner union in the Hulkbuster armor and the subsequent butt-kicking of Thanos' (Josh Brolin) Black Order underling Cull Obsidian faded fast, and they realized they absolutely couldn't include that in the film.
"It didn't work. It was the wrong tone for the movie," said Markus. "A big sequence where you see the union takes away from the attention of the story."
There was a big problem standing in their way, though: by that point, they and directors Joe and Anthony Russo had already filmed Avengers: Endgame, where Banner was already Smart Hulk. Thankfully, this seemingly insurmountable issue was solved with reshoots. Markus and McFeely re-worked the Endgame script, Banner actor Ruffalo came back to set to re-film some sequences, and the theatrical cut of Infinity War was permanently changed.
As fans will recall, what actually ends up happening with Banner in the third act of Avengers: Infinity War is that he does indeed join his fellow heroes to take down Thanos and his army of aliens across the plains of Wakanda. And yes, he does slip into Tony Stark's (Robert Downey Jr.) Hulkbuster armor. But Banner doesn't fight the good fight as Hulk — he simply appears as himself. The reason? Banner had trouble bringing Hulk to the surface after his initial scrap with Thanos at the start of Infinity War, when the Mad Titan hijacked the ship of the asylum-seeking Asgardians. Following that tussle, which resulted in the death of Loki (Tom Hiddleston), Banner couldn't "Hulk out" no matter how hard he tried.
What was confusing about Banner's actual arc in Avengers: Infinity War was that it contradicted the plot points teased in the film's trailers. A few of them featured Hulk in his full green glory fighting side by side with Earth's Mightiest Heroes, and had fans crossing their fingers that the verdant vigilante would bring Thanos to his knees via a hearty Hulk smash. When audiences learned, after seeing Infinity War on the silver screen, that Hulk didn't show up during that final fight, it was believed that the clips shown in the trailers were examples of Marvel intentionally misdirecting fans to keep spoilers at bay. With Markus and McFeely's recent reveal, it stands to reason that the clips of Hulk in the Infinity War trailers may have been the footage that the film's team shot before the big change was made.
In the end, Professor Hulk appears in Avengers: Endgame after the five-year time jump from 2018 to 2023. The film offered a simple explanation as to how the Banner-Hulk union happened: Banner spent 18 months in the gamma lab before finding a way to fuse his smarts with Hulk's strength. Professor Hulk shares the information with his Avengers pals (the ones who weren't dusted at the time) over breakfast, where he wolfs down a bunch of pancakes and takes selfies with a group of young admirers.
Markus said of the moment in Endgame, "A scene where Hulk eats a stack of pancakes [...] I've never seen that in a movie." He added that he didn't feel a need to go into any more detail about Professor Hulk's existence, as he and McFeely were still focused on finding the right mix of seriousness and silliness in Endgame.
While it would have been cool to see Banner and the Hulk collide, Professor Hulk break free from the Hulkbuster armor, and the smart green guy lay down the law in a physical smackdown in Avengers: Infinity War, we agree with Markus and McFeely's ultimate decision to save Smart Hulk for Avengers: Endgame. Both it and Avengers: Infinity War received rave reviews for their perfect balance of action and emotion. Had the screenwriters stuck to their original plan, reception may have been different. And, like Markus said, we also wouldn't have gotten to see Hulk inhale a pile of flapjacks while flexing his muscles for fans. And who would want to live in a world like that?