Avengers: Infinity War screenwriters Christopher Markus and Stephen McFeely admit a deleted scene depicting the birth of Smart Hulk (Mark Ruffalo), the melding of Bruce Banner's brain and the Hulk's brawn, just "didn't work." The scene, which only recently surfaced when it was included in the Marvel Studios Infinity Saga box set, would have seen the brainy Hulk emerge for the first time in Wakanda during a battle between Banner — wearing the specialized Hulkbuster armor developed with Tony Stark (Robert Downey Jr.) — and Black Order heavy-hitter Cull Obsidian (Terry Notary), while Thanos (Josh Brolin) and his army invaded Black Panther's (Chadwick Boseman) homeland for the final Infinity Stone embedded in Vision's (Paul Bettany) head.
"This scene did originally involve the birth of Smart Hulk. Filmed it and everything," Markus tweeted from @ComicBook while live tweeting Infinity War during the latest edition of #QuarantineWatchParty. "Ruffalo was genius, arguing with himself. Didn't work for beans."
The screenwriters previously explained Banner's evolution into Smart Hulk "came at the wrong time," happening just minutes before Thanos used the collective power of the six Infinity Stones to eliminate half of all life in the universe. Hulk's transformation was cut from Infinity War and held back for Avengers: Endgame, where it was revealed Banner achieved harmony with the Hulk after spending 18 months in a gamma lab.
"There was a time when Banner became Smart Hulk in [Infinity War]. It was a lot of fun, but it came at the wrong moment. It was an up, right when everyone else was down," Markus previously told The New York Times. Added McFeely, "His arc was designed like, I’m not getting along with the Hulk, the Hulk won’t come out. And then they compromise and become Smart Hulk."
The process occurred off-screen, during the five-year period skipped over at the beginning of Endgame. During last year's San Diego Comic-Con, the former Marvel Studios scribes explained why Smart Hulk's origin happened off-screen:
"Imagine the first act of Endgame, he's Smart Hulk in all of those scenes — meaning when he goes to kill Thanos, when [the Avengers are] sitting around the compound when Tony's returned — so that required some adjusting," McFeely said. "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."
Added Markus, "Also, it's like, you get it. Part of the thing we learn every time you write a movie — and particularly a movie where it’s a continuing storyline — you don't have to explain as much as you think you have to. You can go to Queens, people know who Spider-Man is. I don’t need to see him get bitten by the spider again. Like, 'okay, he’s a combination of Hulk and Banner, I get it.' Just give me a crumb as to how it happened."