Robert Downey Jr. as Tony Stark + Jeffrey Dean Morgan as the Comedian – Celebrity Doppelgangers
Floppy yet styled 'do? Check. Groomed facial hair? Check. Sexy brooding expressions? Double check.
Downey has reprized his role as superhero Iron Man/billionaire Tony Stark in four separate Marvel movies and is so great at the role because he's basically playing a past version of himself: an alcoholic playboy with piles of cash.
Morgan did an equally fabulous job in his role as the narcissistic, volatile "superhero" the Comedian, falling in and out of the grey area of truth, justice and the Comedian way. So much so that we even forgave him for not being Robert Downey Jr. when we found out the truth.
Sadly, a crossover is impossible due to DC/Marvel universe reasons. Not to mention the fact that it would make Alan Moore's head implode.