It is rare to see DC Comics and Marvel Comics crossover with each other, but in one particular crossover, Iron Man fought. Though the two heroes are very different, Hal Jordan learned from Tony Stark to create his very own Iron Man suit.
The Marvel/DC crossover Unlimited Access serves as a follow-up to 1996's DC vs. Marvel event by Ron Marz, Peter David, Dan Jurgens, and Claudio Castellini. In the follow-up, Access, an original hero introduced in DC vs. Marvel, inexplicably goes back in time to before the events of that crossover. As a result, with neither team recalling the repercussions of their last war, the Justice League and The Avengers end up butting heads and, representing each other's teams (and, by proxy, each other's universes), Green Lantern and Iron Man come face to face.
In Unlimited Access #3 by Karl Kesel and Pat Olliffe that Hal Jordan and Tony Stark feel compelled to tussle with each other after Tony mocks Hal's ring. This gives Hal the idea to use his Green Lantern ring to manifest an Iron Man armor. Most readers will agree that it's pretty awesome to see Green Lantern get his own Iron Man armor. However, the moment is far bigger than even that. What is most impressive about this is the fact that Hal's Green Lantern energy manifested Iron Man suit mimicked Tony Stark's Iron Man suit so perfectly that it was actually on par with Tony's original suit.
In the context of classic Iron Man lore, it takes complicated technical means to construct the perfect suit for Tony Stark. Never mind the actual mechanical constructs that make up the machine itself (although those are extremely important), but it is all powered by a metal plate infused into the middle of his chest that doubles as a source that powers both his heart and the armors. In theory, for anyone else at least, constructing an Iron Man armor that's on par with Tony's suit (if not stronger than Tony's suit) is easier said than done, hence why so many have tried and failed in the past.
Hal Jordan, however, technically, only needed the power of his imagination to perfectly duplicate Tony Stark's Iron Man suit in a way that puts himself in an even match-up with the original. As if it was not already evident enough to readers, this really shows off just how powerful the Green Lantern ring is, even against the powerful technology of Iron Man.
