Robert Downey Jr. was already known as a talented actor before he signed on to play Tony Stark/Iron Man, but his time in the Marvel Cinematic Universe over the last decade propelled him to a new level of fame. Like any other actor, Downey is hired to read lines off a script, but he's also known for improvising, including most recently in Avengers: Infinity War. In fact, director Shane Black noted that during his time on Iron Man 3, Downey would frequently cut scenes short so that they could quickly rewrite the dialogue. While talking about how he and his team were writing new material even during the production of his upcoming movie, The Predator, Black recalled:
And, on Iron Man , Downey would be like, 'Time!' and I'd be like, 'We're shooting!' and he'd be, 'No, shut the cameras' and we'd go back to the trailer and we'd all write, because he wanted new lines. I mean, maybe it's a little bit of that. Maybe I took a lesson from him. We've had a great deal of fun incorporating input from talented people who haven't been looking at the same pages for two years.
Shane Black took over helming duties from Jon Favreau for Iron Man 3, and compared to the previous two Iron Man movies, the threequel definitely felt different. But as Black mentioned to CinemaBlend's own Eric Eisenberg during a set visit for The Predator, even some of what was originally written for Iron Man 3 didn't make it into the final cut, as Downey kept asking for certain moments to be rewritten right then and there. Making sudden rewrites isn't always a good course of action when making a movie, especially a blockbuster, as there's a process laid out ahead of time to ensure that the story flows properly and production runs smoothly. But even then, Downey had enough pull, both as Iron Man 3's star and the guy pretty much anchoring the MCU, to change lines that he felt weren't working. Judging by what Black said, it sounds like he adopted a similar mindset when working on The Predator.
While Iron Man 3 is certainly one of the more polarizing MCU movies among fans (the Mandarin twist continues to be debated), for the most part it was received well among critics, ranking at 80% on Rotten Tomatoes. It marked the end of the Iron Man film series, though Tony Stark has continued to be an important player in the MCU through the Avengers movies, Captain America: Civil War and Spider-Man: Homecoming. While nothing has been officially announced yet, Robert Downey Jr. appears to be wrapping up his time in this massive franchise, meaning that next year's Avengers 4 may be the last time we see him playing the genius billionaire playboy philanthropist.
You can currently see Robert Downey Jr. playing Tony Stark in Avengers: Infinity War, and he'll return for Avengers 4 on May 3, 2019. If you're interested in learning what other MCU projects are in development, look through our Marvel movies guide. As for Shane Black, you can see how his work on The Predator turned out when it is released on September 14.