With the upcoming release of Avengers: Endgame, it looks like the MCU is about to see its biggest shake-up ever. That would be no small feat, considering the absolute devastation audiences felt at the end of Avengers: Infinity War. Now might be a good time to revisit that film, just in case you need to remind yourself of how we got to this point: Tony stark floating through space, Captain America and Black Widow left alone in the Avengers compound, and, of course, Ant-Man and Hawkeye making their much-anticipated returns. A lot of work has gone into both of these films, and that means that there are plenty of great stories from behind the scenes, involving the actors, the filmmakers, and everyone else who worked on the sets of these groundbreaking movies.

Throughout the writing and filming of Avengers: Infinity War, there were a lot of interesting things that were added or taken out of the film. There were some interesting decisions made by the actors, as well, and ultimately everything added up to make one of the most exciting and jaw-dropping films of the year. Whether it was minor script changes, scenes that were taken out entirely, or even just an ad-libbed conversation between two of the reunited heroes, all of these little things turned into something that was greater than the sum of its parts. If anything, these 20 behind the scenes revelations from Avengers: Infinity War show just how much work, heart, and passion went into making the biggest superhero film of all time (so far).

20 ROBERT DOWNEY JR. REFUSED TO WEAR A MOCAP SUIT

All of the actors in the MCU put in a lot of work for their performances, and one of the things that many of them have to endure is wearing a motion capture or MoCap suit. Tom Holland, in particular, never actually wears a Spider-Man suit. His whole appearance is done through motion capture.

However, one actor was not having it with this MoCap suit business. According to an on-set report from Digital Spy, Robert Downey Jr. flat out refused to wear such a suit, instead opting to wear black pants and his Iron Man breastplate. "They tried to get one of these on me, but no," Downey Jr. said.

19 EARLY DRAFTS GAVE THE BLACK ORDER MORE BACKSTORY

One of the biggest additions to Avengers: Infinity War was Thanos's loyal team of followers known as the Black Order. While each of these characters had a distinct personality and set of powers, there was actually going to be much more to them in early drafts, including a lengthier backstory.

According to the feature commentary on the Blu-ray release, the Black Order's origins would have been explored in the film, except for the fact that it would have just been too much to add. According to co-director Joe Russo, "Ultimately the movie was getting too crowded, too hard to follow."

18 PETER'S SPIDER-SENSE WAS FILMED WITHOUT CGI

One of the first scenes that people saw in the original trailers for Avengers: Infinity War was Peter Parker's spider-sense being activated by the giant ship hovering over Manhattan. This was shown in the form of Peter's arm hair standing up on end, alerting him to the danger looming over the city.

In a film with so many visual effects, it seems like this could have been done with CGI. However, it was entirely practical. In the commentary for the film, the Russo Brothers reveal how the shot was achieved. "A lot of people think it's a CG shot," Anthony Russo says, "but it was actually achieved by a very gentle blowing on Tom's ear."

17 THE HAIR CONVERSATION WAS AD-LIBBED

There were so many big stars in Avengers: Infinity War, that people often forget that the one people were most excited for was Captain America's new beard. When it was revealed in the first trailers for the film, people really got on board with the characters new look. It was even noted in the film by another bearded superhero, Thor.

Both he and Steve Rogers take a moment to compliment each other's new looks on the battlefield, and the moment was made up on the spot. According to Entertainment Weekly, it was Evans who suggested that the two old friends comment on each other's appearances in order to make their reunion just a bit more fun and realistic.

16 THANOS HAD TO MAKE A FIST TO USE THE STONES

With an enemy as powerful as Thanos wreaking havoc all over the galaxy, it would have been hard to make the case that the heroes could have a realistic chance of beating him. Even when they got close, it still took all of their combined efforts and strength to get a good shot at the Mad Titan.

The Russo Brothers knew that they would need to have a rule that could give the heroes a slim shot at beating Thanos. In the Blu-ray commentary, co-writer Stephen McFeely revealed that they came up with the rule that Thanos had to make a fist in order to use the infinity stones, in order to give the heroes a fighting chance and to put a limit on the gauntlet's power.

15 ROBERT DOWNEY JR. BOUGHT PERSONALIZED CHAIRS

Undertaking a film as expansive and expensive as Avengers: Infinity War takes a huge cast and crew working as hard as they can. Although the audience only sees the stars on-screen, there are always plenty of people on set without whom the movie just wouldn't have happened.

Robert Downey Jr., having been a working actor in Hollywood for decades now, knows that movies don't happen without hard work from a great team, which is why he thanked the entire cast and crew with personalized chairs, according to Cinemablend. Each one had the crew members name and the film's logo stitched in the fabric, as well as an engraved plate which reads "heartfelt thanx from the bottom of my arc reactor."

14 THE "SPACE DOGS" WAS ADDED AFTER A TEST SCREENING

During the climactic battle of Wakanda in Avengers: Infinity War, the heroes, as well as the armies of Wakanda, are forced to face off against the Outriders, a genetically engineered race of creatures designed to obey their master's orders at any costs. At one point, Rocket Raccoon notes their canine appearance by calling them "space dogs."

This line was not originally in the script and actually came from a focus group that took place after a test screening. In the Blu-ray commentary, Anthony Russo notes that someone was talking about the scene and said, "You know those space dogs?" The filmmakers thought that was hilarious and added it to Bradley Cooper's script.

13 BANNER AND HULK HAVE A DYSFUNCTIONAL RELATIONSHIP

Fans who were waiting to see the Hulk in action in Avengers: Infinity War had to be at least a little disappointed when it became evident that the big green guy was not coming out to play. The prevailing theory was that the Hulk had been rendered afraid by the beating he took from Thanos, but the story was actually far more interesting than that.

The dynamic of Banner's and Hulk's relationship was revealed in the Blu-ray commentary. "Ultimately what it is is that he's tired of playing hero to Bruce Banner," said Joe Russo. Co-writer Stephen McFeely also noted that each character's arc had to be summed up as briefly as possible, so Banner's was just "Banner has to rely on himself."

12 "STRANGE ALCHEMY"

One of the most exciting parts about Avengers: Infinity War was that so many heroes would finally be meeting each other for the first time. Obviously, a few of them had worked together before, but fans couldn't wait to see Tony Stark meeting Peter quill or Spider-Man chatting with Doctor Strange.

As Joe Russo mentions in the film's commentary, the idea of having characters meet was referred to as "strange alchemy." The filmmakers said they took a lot of time to decide which heroes would bring out the most in each other. Russo said, "we knew that this movie, in particular, being a crossover event that what would be some of the most entertaining stuff in the movie is how these characters who have never interacted before would interact."

11 ALMOST EVERY SHOT IS A VISUAL EFFECTS SHOT

A film as huge as Avengers: Infinity War, which features plenty of superpowered action is bound to have a lot of visual effects shots. Those shots are what make the movie come alive, and bring a lot of power to the story. While the film is not made entirely of visual effects shots, it comes pretty close to being just that.

According to Executive producer Victoria Alonso, who is interviewed in a Blu-ray featurette, the film is composed of 3000 shots, 2900 of which are visual effects shots. That means that roughly 96% of the scenes throughout the film contain visual effects, leaving just about 1 in every 25 shots to be done entirely by practical means.

10 LOKI WAS TAKEN OUT EARLY TO RAISE THE STAKES

Avengers: Infinity War didn't pull any punches. Right from the first scene in the film, it is clear that this is going to be a movie with major losses, the first of which is Loki, who meets his end at the hands of Thanos after giving up the tesseract in order to save his brother, Thor. 

This was done intentionally by the filmmakers to put the audience on edge. In the Blu-ray commentary for the film, Joe Russo said, "we wanted to knock you off-kilter and make the audience understand that the stakes were going to be significant and the cost was going to be very high in the movie."

9 EBONY MAW'S FATE WAS INSPIRED BY INDIANA JONES

When Tony Stark and Peter Parker find themselves on board the Black Order's massive spaceship, they must face off against Ebony Maw, a member of the Black Order with significantly dangerous powers in order to free Doctor Strange and protect the time stone. It might have been a really difficult fight, except for the fact that it wasn't.

Ebony Maw gets blown into space through a hole in the ship's hull after Peter Parker makes a crack about that "really old movie" Aliens. However, the moment was inspired by an entirely different movie. In the film's commentary track, Joe Russo revealed that Ebony Maw's defeat drew its inspiration from the scene in Raiders of the Lost Ark, where rather than fighting an enemy, Dr. Jones just decides to save time and shoot him.

8 CAPTAIN AMERICA WAS SUPPOSED TO APPEAR LATER

Captain America's appearance when he swoops in to save the day in Scotland was an awesome reveal. However, if things had stayed the same from some of the earlier drafts of the script, then Steve Rogers would have made a much later entrance to the film. In fact, he wouldn't have appeared until the 2-hour mark.

In the film's commentary, co-writer Stephen McFeely says that in an original draft, Cap didn't appear until he tackles Corvus Glaive in order to save Vision. Joe Russo noted that having Captain America show up so late would have been made to feel like Lancelot finally arriving in John Boorman's Excalibur.

7 CHRIS HEMSWORTH DIDN'T WANT A SERIOUS THOR

Thor had always sort of been the stodgy, disconnected character in the earlier Avengers films, most likely due to the more antiquated nature of where he came from. However, that all changed in Thor: Ragnarok, which gave the character a much-needed boost of humor. Chris Hemsworth loved the change and wanted it to continue in Avengers: Infinity War.

According to an on-set report from Cinemablend, Hemsworth worried that his character would go back to the way he used to be. "I came into this and called Joe and Anthony and said, 'Look, don't write me the old Thor," Hemsworth said, "we've got a new Thor now." Thor got to keep his newfound sense of humor, and even got to riff with the Guardians of the Galaxy.

6 ROBERT DOWNEY JR. REWROTE SOME OF HIS SCENES

Robert Downey Jr. is sort of the patriarch of the Marvel Studios family, having been the guy whose role as Tony Stark kicked off the whole thing. He's always been a major fixture of the universe, and fans are obviously both excited and afraid to see what the future holds for Iron Man in Avengers: Endgame.

Downey Jr. is so in touch with this character, having played him for ten years now, that he often worked with The filmmakers to re-write his scenes. During an on-set visit, Joe Russo told Digital Spy "we sat down with Robert to get as much authenticity as we could in the scene -- and to get all of those colors of Tony Stark that Robert knows better than anybody."

5 THE "TUNA MELT" LINE WAS IN EVERY DRAFT OF THE SCRIPT

When working on a film with as much story to tell as Avengers: Infinity War, there are bound to be a lot of script changes. That was definitely true of the sprawling, world-spanning story of the movie, whose script underwent countless re-writes and new drafts, even while the movie was being shot.

However, there was one singular line that made it all the way from the very first draft to the big screen: Wong's now famous "I wouldn't say no to a tuna melt," quip was practically the only thing that persisted throughout every iteration of the film's script, according to a conversation during the film's commentary track.

4 THANOS ON XANDAR WAS CUT FOR BEING REPETITIVE

It is revealed through dialogue that Thanos got the Power Stone from Xandar, but fans still wondered why they didn't get to see Thanos acquiring that Stone themselves. Considering the film was already two and a half hours long, it made sense to leave the scene out, but there was an even more logical story reason not to include it.

In the film's commentary track, the filmmakers reveal that they had discussed including a scene of Thanos acquiring the Power Stone, but ultimately decided to cut it because it would have been too repetitive. "If Thanos went to Xandar to get that stone, you know what happened," said writer Christoper Markus, "It was a big battle and he got it."

3 TONY AND STEVE MET UP IN EARLY DRAFTS

Part of what made Avengers: Infinity War such a heartbreaking film was the fact that the Avengers had been separated by the events of Captain America: Civil War, meaning they were unable to work together to try and stop Thanos from achieving his goals. However, in an early draft of the script, Tony and Steve did end up meeting at one point.

In the film's commentary track, the filmmakers reveal that they had planned to have a scene of Tony and Steve meeting each other early in the film. However, they ultimately decided against it, with Stephen McFeely saying "We tried in a few drafts and it ground things to a halt."

2 MARK RUFFALO AND TOM HOLLAND WERE GIVEN FAKE SCRIPTS

After most people had a chance to see Avengers: Infinity War and it was pretty much safe to start talking about the ending, people started remembering how Mark Ruffalo had basically ruined the entire thing in an interview. This was in spite of the fact that because Ruffalo is so prone to revealing secrets, he was actually given a fake script by the Russo Brothers.

However, Ruffalo wasn't the only person who had trouble keeping spoilers for the film under wraps. Tom Holland was also given a fake script before filming started so that he would not reveal any important details prior to the film's release. He still let a few things slip, which is why Benedict Cumberbatch was sent in to basically babysit him in interviews.

1 ACTUALLY, THE WHOLE CAST WAS GIVEN FAKE SCRIPTS

As much as Tom Holland and Mark Ruffalo needed to have fake scripts given to them, they were not the only cast members who received fake scripts. In fact, every actor in the film was given a script that was not anywhere near what was actually going to be filmed, in order to protect the film's secrets from absolutely everyone, a strategy that worked very well.

"We wrote fake pages for the script, we distributed fake pages. None of the actors have actually read the entire script," Joe Russo told Kinowetter ahead of the film's release date, "We really feel like this is one that people need to see quickly before anybody spoils it for them." The same strategy was probably used while filming Avengers: Endgame.