Endgame directors Joe and Anthony Russo revealed on MTV's Happy Sad Confused podcast that they filmed the scene with Langford that would have mirrored an Avengers: Infinity War scene in which Thanos (Josh Brolin) saw a younger version of his daughter Gamora after he used the Infinity Gauntlet to wipe out half of all life in the universe.

"There was an idea that Tony was going to go into the metaphysical way station that Thanos goes in when he snapped his fingers, and there was going to be a future version of his daughter in that way station," Joe Russo said. "We showed it to a test audience and it was really confusing for them."

Added Anthony Russo: "We didn't feel an emotional association with the adult version of his daughter. It wasn't ringing to us. It wasn't resonating to us on an emotional level is why we moved away from it."

The idea would have been that after Tony Stark sacrificed his life by using the Infinity Gauntlet to kill Thanos and his minions, that Morgan would forgive him for leaving the family behind.

"His future daughter forgave him and gave him peace to go. The idea felt resonate, but it just was too many ideas in an overcomplicated movie," said Joe Russo.

For the Russo Bros., Tony Stark's final moments were among the most challenging to get right. As they told The Hollywood Reporter previously, the filmmakers pitched Tony Stark's death to Downey out of respect for his contributions to the Marvel Cinematic Universe.

"I think Downey may have had mixed emotions about thinking about [where Tony Stark ends up in Endgame], but I think at the end of the day, he totally accepted it," Anthony Russo told THR.

And at a Q&A in Washington, D.C. moderated by NPR's Linda Holmes last week, they revealed that Downey's final line ("I am Iron Man") was added in reshoots after editor Jeff Ford suggested it.