Stan Lee's cameos in Marvel movies are one of the best things about the films!

It was incredibly hard for comic book fans to come to terms with the news of his passing, and even more so, because the only constant link in the films was now lost. Since 2000, Stan Lee has appeared in 60 cameos in the Marvel Cinematic Universe films.

From his unsuccessful attempts at lifting Mjolnir to playing a World War II veteran who indulged in far too much of Thor's Asgardian liquor, there have been several memorable ones...but there's one far more important than the others.

RELATED: Here's Everything We Need To Know About Stan Lee's Cameo In 'Endgame'

The most significant Stan Lee cameo arrived with Guardians Of The Galaxy Vol 2. Stan Lee was seen talking to a group of Watchers and sharing his experiences of the universe, which suggested he was one person wearing different capes, in an attempt to keep an eye on the Earth's mightiest heroes.

You'd think only James Gunn could've come up with this, but that's unfortunately not true.

James Gunn Stole The Idea From Fans

There are tons of Easter eggs in Marvel films, which are often carefully placed with the intention to drive fans crazy. Today, Guardians Of The Galaxy director James Gunn revealed he stole the overarching plot, that Stan Lee could be a Watcher informant, from fans who shared theories to Twitter!

Earlier today, a user shared a compiled look at every Stan Lee cameo to Twitter, citing that he was "canonically a Watcher informant, playing the same character in ever MCU movie, keeping an eye on the heroes and their adventures".

James Gunn shared the tweet, adding "I stole the idea from fan theories on Twitter, which I thought were hilarious."

RELATED: Director James Gunn Reveals Upcoming ‘The Suicide Squad’ Movie Will Be Rated R

Another fan asked Gunn if Marvel would've decided to cast Stan Lee as the older version of Captain America (in Avengers: Endgame), if he hadn't passed.

"No. I'm not sure that would be the right spot for a laugh," the director replied.

James Gunn is infamous for sharing behind-the-scenes stories from the Marvel film sets, and had a hilarious story to share about Chris Pratt, aka Star Lord.

In a conversation which discussed actors unknowingly mouthing their colleagues' lines along with them, Gunn announced that Chris Pratt accidentally made "pew pew" sounds while firing space guns.

According to Gunn, the actor wouldn't realize he was doing it, until it was pointed out.

"I'm not sure if this is in the moment or insane, but it's one of my favorite things," Gunn said.

NEXT: Here's Why Bradley Cooper Was Cast To Voice Rocket In ‘Guardians Of The Galaxy’