Avengers: Endgame screenwriters Christopher Markus and Stephen McFeely have expanded on the decision to skip over a detailed backstory for Smart Hulk (Mark Ruffalo), who was originally planned to debut in the Wakanda-set climax of Infinity War.
"We wrote [Infinity War], we shot it, and then went on to shoot most of Endgame. And it was: he achieved union with the Hulk while inside the Hulkbuster, burst out, and kicked Cull Obsidian's ass. And it didn't work," Markus said at San Diego Comic-Con.
"It was completely the wrong tone for that moment in the movie. It was this victory when we were headed toward a crushing defeat, and it was tone deaf. But we had already shot Endgame, where he was already Smart Hulk."
The scribes then recognized the unseen five years skipped over following Thanos' (Josh Brolin) erasure of half of all life in the universe meant Bruce Banner and the Other Guy could achieve unity off-screen, avoiding the addition of a lengthy origin story to Endgame's already three-hour runtime.
"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," 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."
Hulk's heroic eruption from the Hulkbuster following his refusal to show for much of Infinity War — a moment depicted as part of the Infinity War merchandise line — then became a necessary sacrifice.
"Part of the challenge and part of the pleasure of this giant task of these two movies is, how do you tell everything you need to tell, weave it together, and keep it light enough so that you're not bogging down all the time? And a big sequence where you see these two guys achieve union takes time, and takes attention away from the story," Markus said.
"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. Let's accept that challenge and try to push the whole thing forward, push the genre forward."
Avengers: Endgame is available to own on Digital HD July 30 and on 4K Ultra HD and Blu-ray August 13.