Avengers: Endgame Photo of Joe Russo and Baby Ant-Man is Adorable

There was no shortage of amazing moments in Avengers: Endgame, which served as the culmination to over 20 films spanning longer than a decade in the Marvel Cinematic Universe. But for every epic payoff, there were also tons of laughs packed into that three-hour runtime. And one of the funniest moments came in the Avengers' first experiment with time travel at the expense of Ant-Man.

The scene showed Scott Lang as the test subject for time travel, being turned into a teenager, an old man, and then a baby, before returning to his normal age. Though Tony Stark eventually solves this problem, Ant-Baby's appearance was definitely a highlight in the film.

Director Joe Russo & Baby Scott Lang (Paul Rudd) on the set of Avengers: Endgame. from r/marvelstudios

Of course, if you spend too much time thinking about the time travel rules in the film, you'll likely drive yourself insane. Event he film's writers and directors disagree on the rules established in the film. Whether it comes down to parallel universes or changes to the time line, it's obvious that we'll have to wait and see what happens to the MCU because of the actions from Avengers: Endgame.

Co-writer Christopher Markus explained to Fandango that the removal of an Infinity Stone is what actually creates a new timeline, and that other minor changes don't affect the fate of the universe.

"That is our theory. We are not experts on time travel, but the Ancient One specifically states that when you take an Infinity Stone out of a timeline it creates a new timeline," said Markus. "So Steve going back and just being there would not create a new timeline. So I reject the 'Steve is in an alternate reality' theory. I do believe that there is simply a period in world history from about '48 to now where there are two Steve Rogers. And anyway, for a large chunk of that one of them is frozen in ice. So it's not like they'd be running into each other."

Meanwhile, Joe Russo gave an entirely different alternative while speaking to Tencent, saying that Captain America created a parallel world when he decided to stick around in the past after returning the Infinity Stones to where they belonged.

"The time travel in this movie created an alternate reality," Joe Russo explained. "He lived a completely different life in that world. We don't know how exactly his life turned out, but I'd like to believe he still helped many others when they were needed in that world."

Avengers: Endgame is now playing in theaters.