Robert Downey Jr. is set to return to the Marvel Cinematic Universe (MCU) as Doctor Doom in the upcoming film 'Avengers: Doomsday,' following a resurgence of interest in an old audition tape for his iconic role as Iron Man. The audition video, which has gone viral, showcases Downey Jr.'s impressive ability to switch between Tony Stark's charming persona and serious moments, highlighting his suitability for the role. Initially considered for Iron Man were other actors, including Tom Cruise, but Marvel ultimately chose Downey Jr., a decision that led to significant success for the franchise. Downey's portrayal has left a lasting impact, and he is expected to earn around $200 million for his comeback in the MCU. Directed by the Russo Brothers, 'Avengers: Doomsday' is scheduled to start filming in 2025 and release in 2026. The nostalgic response to the audition tape underscores Downey's enduring legacy within the superhero genre.