Nearly 20 years after Indiana Jones and the Last Crusade hit theaters, Steven Spielberg, George Lucas, and Harrison Ford returned for Indiana Jones and the Kingdom of the Crystal Skull. Indy’s fourth adventure got mixed reviews at the box office, and many people credit Kingdom of the Crystal Skull as the worst film in the series.

Related: Indiana Jones: 10 Things You Probably Didn't Know About Raiders Of The Lost Ark

The film saw Indy going against the Soviets as they both race to uncover the truth of the Crystal Skulls. Kingdom of the Crystal Skull of course brought back Harrison Ford back, but also saw the return of Karen Allen as Marion Ravenwood and introduced their son named Mutt (played by Shia LaBeouf). The movie has been out for over 10 years, but there are some things you might not know about the film. Here is Indiana Jones: 10 Things You Probably Didn’t Know About The Kingdom Of The Crystal Skull.

Shia LaBeouf Partly Blames Himself

Indiana Jones, Mutt and Marion in a truck in Kingdom of the Crystal Skull

With Indiana Jones and the Kingdom of the Crystal Skull being a disappointment to many, people often wonder who is to blame for the film. With that in mind, Shia LaBeouf partly blames himself. In an interview with the Los Angeles Times, LaBeouf stated, “You get to monkey-swinging and things like that and you can blame it on the writer and you can blame it on Steven [Spielberg, who directed]. But the actor's job is to make it come alive and make it work, and I couldn't do it. So that's my fault. Simple.”

In the special features for the Kingdom of the Crystal Skull DVD, Harrison ford praised LaBeouf and had nothing but nice things to say about him, but after LaBeouf’s comments, Ford called LaBeouf a “f***ing idiot” and slammed him for criticizing the film

Sean Connery Could Have Returned

Sean Connery in Indiana Jones and the Last Crusade.

Sean Connery played the first version of 007, but he also appears in the Indiana Jones franchise. Connery starred alongside Harrison Ford as Henry Jones in Indiana Jones and the Last Crusade. People loved the father and son dynamic in the third film, and Connery could have returned for the fourth.

Connery was offered a cameo role in Kingdom of the Crystal Skull, but turned down the part because he didn’t want to come out of retirement for such a small part. He recommended to Spielberg that it would be better to kill off the character instead, which ultimately happened in the film.

Steven Spielberg’s Daughter Has A Cameo

Harrison Ford and Shia LaBeouf in Indiana Jones and the Kingdom of the Crystal Skull

Steven Spielberg is one of the most famous directors in Hollywood, but his daughter became an actress. Sasha Spielberg has acted in over a dozen films in her career, including Indiana Jones and the Kingdom of the Crystal Skull. Sasha appears in the film during the bar scene and is the woman who hits Mutt in the face.

Related: Indiana Jones: 10 Things You Probably Didn’t Know About The Temple Of Doom

For fans that didn’t know, Sasha’s mother was also a big part of the Indiana Jones franchise. Kate Capshaw (Willie Scott) met Steven Spielberg when he made Indiana Jones and the Temple of Doom, who she eventually married in 1991.

George Lucas Insisted They Tackle Aliens

An Alien looks directly into the camera in Indiana Jones Kingdom of the Crystal Skull

One of the biggest criticisms of Indiana Jones and the Kingdom of the Crystal Skull was the introduction of aliens. When George Lucas came up with the idea of aliens in the film, Steven Spielberg said he didn’t want to tackle aliens since he had already made two films about aliens: Close Encounters of the Third Kind and E.T.: The Extra-Terrestrial.

In the featurette “The Return of a Legend”, it was revealed that George Lucas insisted on the idea. He explained that since the first three films were like action serials from the 30s and 40s, Kingdom of the Crystal Skull should be like a science fiction b-movie from the ‘50s.

They Were Initially Concerned About Harrison Ford’s Age

Indiana Jones Kingdom Crystal Skull

When the idea of Indiana Jones 4 turned into a real possibility, Harrison Ford was in his mid-50s. By the time the film was actually released, Ford was 66 but you’d never guess it by the way he performs in the movie.

Steven Spielberg revealed that they were initially concerned about Ford’s age, but it turned out to not be an issue since Ford had always kept himself in such good shape. Ford exercised and went on a diet for the movie, but when he first tried on his costume again, he said it fit like a glove.

The Title Was Almost Ridiculous

indiana jones kingdom of the crystal skull worst special effects blockbusters

In the featurette “Pre-Production”, several of the ideas for the title were revealed. Each person close to the development of the film pitched several titles for the movie, all of which would have likely been hated by fans. Two of the titles George Lucas proposed for the film were Indiana Jones and the Saucer Men and Indiana Jones and the Giant Ants.

Steven Spielberg also pitched Indiana Jones and the "blank" "blank" of the Mysterians, but realized they couldn’t use the title because The Mysterians had already been made back in 1957. Writer David Koepp probably had the worst title idea of all: Indiana Jones and the Son of Indiana Jones.

Indiana Jones Almost Had A Daughter

The father and son dynamic was one of the best parts of Indiana Jones and the Last Crusade and the same concept is presented in Kingdom of the Crystal Skull. However, instead of Henry Jones returning for the film, they turned Indiana Jones into a father. Mutt Williams is revealed as the son of Marion Ravenwood and Indy, but Indiana Jones almost had a daughter instead.

Related: Indiana Jones: 10 Things You Didn't Know About The Last Crusade

In one of the special features for the Kingdom of the Crystal Skull DVD, it was revealed that giving Indiana Jones a daughter had originally been the plan, but Steven Spielberg didn’t like the idea. After some convincing, Spielberg agreed to focus on Indy’s son in the movie.

Shia LaBeouf Was The First Choice For Mutt

Harrison Ford and Shia LeBeouf in Kingdom of the Crystal Skull

In the featurette “Pre-Production” Steven Spielberg explained that Shia LaBeouf was always the first choice for the role of Mutt Williams. When Spielberg saw LaBeouf’s performance in Holes with his kids, Spielberg thought that he would be a great addition to a future Indiana Jones movie.

Spielberg didn’t even consider anybody else for the role, especially since he got the approval of both George Lucas and Harrison Ford. When LaBeouf was offered the role, Spielberg gave the actor the movies, Blackboard Jungle, Rebel Without a Cause, and The Wild One, to base the character on.

They Specifically Avoided Nazis

Indiana Jones and the Kingdom of the Crystal Skull

Nazis were a big part of Raiders of the Lost Ark and Indiana Jones and the Last Crusade, but they weren’t the antagonists in Kingdom of the Crystal Skull. Instead, Indy goes up against the Soviets since the film takes place in 1957. Spielberg didn’t want to focus on Nazis again especially since he had directed Schindler’s List in 1993.

Having Soviets be the villains of the film also worked out since there was a 19-year gap between the release of Indiana Jones and the Last Crusade and Indiana Jones and the Kingdom of the Crystal Skull, which is the same amount of time that is passed within the narrative of the films.

The Adventure Isn’t Over

Indiana Jones 5 release date delay explained

While Indiana Jones and the Kingdom of the Crystal Skull wasn't what a lot of fans were hoping to see, Steven Spielberg could redeem himself with Indiana Jones 5. Indiana Jones 5 has been delayed several times since it was announced, but the film is expected to hit theaters in 2021.

Harrison Ford will once again be playing the famous archeologist, with Spielberg returning to direct, George Lucas returning as an executive producer, and John Williams returning as a composer. Very little is known about the story of the film, but it’s been confirmed that Shia LaBeouf will not be putting on Indy’s fedora in the next adventure.

Next: Indiana Jones 5: 10 Scrapped Ideas From Previous Sequels It Should Use