Robert Downey Jr. Auditioned To Play Doctor Doom In 2005's Fantastic Four

Before he was Tony Stark, Robert Downey Jr. was in the running to play a different armor-wearing genius from the Marvel universe.

For the 15th anniversary of 2008's "Iron Man," Marvel Studios president Kevin Feige and director John Favreau sat down for a conversation. When discussing RDJ — who the success of "Iron Man" rests on more than anyone else — Favreau mentioned that Feige and Marvel were already familiar with him when he was cast. Why? The actor auditioned to play Doctor Doom in the 2005 "Fantastic Four" film. (Feige is credited as an executive producer on the film.) It's unclear how far along RDJ got, but the part ultimately went to Julian McMahon.

Watching McMahon's performance, it makes sense why RDJ was in the running. Doom in the "Fantastic Four" film duology doesn't have much in common with the comics' Doctor Doom. Instead of a sorcerer-dictator, he's a tech CEO, more like Tony Stark but without the heart of gold. He's arrogant but not theatrical — never referring to himself in the third person — and McMahon plays him with boilerplate condescension, not grandiosity. If you have Doom speaking in corny zingers ("Let's all go for a spin!") instead of soliloquies, you've done something very wrong.

RDJ probably would've done as fine a job as could be with this Doom. His career definitely benefited from him not getting the part, though.

Robert Downey Jr.'s career infamously took a downturn in the 1990s due to his substance abuse and addictions. He was arrested several times and struggled to be insured on productions. Thankfully, Downey prevailed over his disease and his career had an upswing in the 2000s. The fact he was considered to be in a blockbuster like "Fantastic Four" was a sign of the coming upswing. However, the films wouldn't have been the career kickstarter he needed. They earned unflattering reviews and middling box-office returns. Maybe RDJ bringing some extra charisma as Doom would've given them a boost, but there's only so much he could do alone.

The long-term ramifications would've also probably been negative. Imagine the world where RDJ can't star in "Kiss Kiss Bang Bang" because of scheduling conflicts with "Fantastic Four," or one where he has to turn down "Zodiac" because he's already booked to shoot the sequel, "Rise of the Silver Surfer." RDJ's fantastic performances in those movies were a huge feather in his cap when it came to restoring his reputation.

Now, the elephant in the room: could RDJ have still played Iron Man with Doom on his resume? It's not out of the question — after all, Chris Evans went from the Human Torch to the MCU's Captain America. The timing would've been cutting it close, though. "Rise of the Silver Surfer" was released in 2007, just a year before "Iron Man." Maybe RDJ wouldn't have been able to accommodate both schedules. Maybe he would've had a bad experience with "Fantastic Four" and decided not to join another superhero franchise.

These possibilities are better left unknown. However, this piece of casting trivia does make Brian Michael Bendis and Alex Maleev's "Infamous Iron Man" a funny read, where a reformed Doom becomes the new Iron Man.