How Iron Man Would Defeat Every Justice League Member
5. Superman
While the Marvel Cinematic Universe has popularised Iron Man's Hulkbuster suit, it may well be Tony Stark's Phoenix-Buster that comes in handy should Shellhead ever butt heads with Superman.
In a case of 'does exactly as it says on the tin', Stark's Phoenix-Buster is capable of toppling the ridiculously powerful cosmic force known as the Phoenix. Y'know, as in the one and the same Phoenix that has been known to regularly turn Jean Grey into the most dominant being in the entire galaxy.
As part of 2012's Avengers vs. X-Men crossover tale, Hank Pym helped Tony in creating what would be the Phoenix-Buster. This particular suit is able to hold off the might of the planet-devouring Phoenix and is literally able to protect the universe. So, while Superman is one of the true powerhouses of comics, the Man of Steel's iron will, heat vision, ice breath, superspeed, flight and enhanced strength would fall short against the smarts and resourcefulness of an Iron Man who has access to his Phoenix-Buster costume.
Superman wouldn't go down without a fight, but Stark has often shown that he's prepared to be truly clinical and underhand if necessary. As such, don't put it past him to have used his vast resources to unearth some green kryptonite to use against the Big Blue Boy Scout, too.