The Incredible Hulk
Back in 1977, you almost wouldn't have liked Arnie when he was angry. Story goes that Richard Kiel (who is most famous for playing Jaws in the James Bond films The Spy Who Loved Me and Moonraker) was cast as the Hulk, but during filming of the pilot episode the producers felt he didn't look menacing enough so sacked him! The hunt was on for a new Hulk, and the choice was between Lou Ferrigno and Arnold Schwarzenegger. In the end Ferrigno won, partly because he stands 3 inches taller than Arnold. By the way, Richard Kiel still appears in the pilot episode. Rather than re-filming all of his scenes a small moment of Kiel Hulk-out was spliced in.
Arnie was amongst the dozens of other actors who were considered for the role of Superman in the 1978 movie. He made it through several cuts, but was eventually struck out of the running by Marlon Brando. Brando's contract gave him a say in the casting of the other main roles, so he voted against Schwarzenegger, his reasoning was the public would not be able to understand him!
In 1987 Schwarzenegger was amongst the actors shortlisted to play Alex Murphy, aka RoboCop. The reason it went to Peter Weller was because Arnie was literally too big for the role. Not in success or anything, but in body size. The producers felt that if a robo-suit was built to hold Arnold’s massive muscular body then he would end up looking like a "live-action version of the Michelin Man".
Well not actually John McClane, but Die Hard could've ended up starring Arnie in the main role. Originally the screenplay was adapted to work as a sequel to the 1985 Arnold Schwarzenegger movie Commando. Basically the same story, just with Arnie's Commando character of John Matrix. Maybe he just didn't want to work with the young Alyssa Milano again, we don't know, either way, Schwarzenegger passed.
In 1991, fresh of the back of their Terminator 2: Judgement Day success, James Cameron wrote a treatment for a Spider-Man movie starring Arnie as Dr. Octopus. Apparently the studio didn't like what he had in mind (maybe it was the thought of Charlie Sheen as the Web Slinger!), and so they passed on the script.
The President of the United States
As Arnie's Expendables co-star, Sylvester Stallone, said "He wants to be President". Well he nearly was. Prior to his days as The Governator, Arnie was in the running to play President James Marshall in 1997s Air Force One. The part was initially offered to Kevin Costner, who turned it down, so producers drew up a shortlist of potential new lead actors which included Tom Hanks, Dennis Quaid, Harrison Ford and Arnold. Presumably because he was the only one who had a surname that was Presidential... Ford got the call.
Castor Troy / Sean Archer13 years before they finally appeared together in The Expendables, Schwarzenegger and Stallone were the two sought out for the leading roles in 1997s Face/Off. Deals could not be struck, so a very unlikely duo of Michael Douglas and Jean-Claude Van Damme was proposed. Douglas did end up serving as Executive Producer when the movie finally started filming with John Travolta and Nicolas Cage changing faces.
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