(Note, potential SPOILERS for all sorts of comics, and possibly a superhero movie or two, are very much to be found below)
Now, with all the recent talk about Marvel's upcoming Captain America: Civil War, and the superhero-on-superhero bludgeoning it's set to feature, it's not too hard to imagine that we're on the verge of seeing at least one of our favorite superheroes transform into a veritable villain.
Now, thankfully, Marvel seem set to go down the same route as their comic-book Civil War, adding sufficient moral complexity to both sides to keep the heroes plausibly heroic in the years that follow - but it still raises an interesting question:
What Would Our Favorite Superheroes Be Like if They Were Evil?
Well, thankfully, some of the world's greatest comic-book creators have wondered much the same thing over the years, which means we actually have a whole bunch of comics available to us that tell us exactly what it would be like if our favorite heroes turned evil.
Iron Man is Currently a Supervillain
Yup, that's right - that picture up above of him electrocuting Daredevil isn't just one of those zany team-ups where heroes face off before discovering that there's a real villain manipulating them into doing so.
Instead, it's the byproduct of the events of Marvel's recent Axis crossover event, in which the moral centers of the Marvel Universe's heroes and villains were reversed, causing heroes to become villains, and villains to become heroes.
Now, at the end of the crossover, pretty much everything went back to normal - expect that evil Tony Stark found a way to protect himself from reverting back to his old self. And, so, in the pages of Superior Iron Man, you can now see exactly what would happen if Tony Stark was a dastardly, egotistical, money-chasing alcoholic.
Otherwise known as 'what he's always like, only slightly more of an asshole'.
Meanwhile, in the DC Universe:
Superman Has an Evil Double (or Twenty)
That's right, even the goody-two-shoes Man of Steel has a few evil versions of himself running around out there - including both Bizarro, a twisted opposite Superman, and the full on evil version of the hero, Ultraman, from the morally-inverted Earth-Three.
Add in the fact that both red and black Kryptonite seem capable of forming evil-ish versions of the hero, and it's really a wonder anyone ever trusts him at all...
Spider-Man Gradually Turned Evil in the Most Predictable Way Possible
That's right - remember how, back in the 80's (and in Spider-Man 3) Spidey ended up wearing a bad-ass black version of his costume, after being bonded with a mysterious symbiote?
Well, it wasn't all that surprising when it turned out that the symbiote was gradually turning him into a darker, more aggressive version of himself - after all, there's a long line of cultural tropes telling us that the black version of any costume is going to be the evil one...
Oh, and of course there was that one time where one of Spidey's clones turned out to be evil - but honestly, he's had so many over the years that the law of averages made that pretty much an inevitability...
Batman Gets Mashed Up With The Joker
Now, Batman's had a fair few evil versions of himself crop up in the actual DC universe - take a bow, Owlman - but arguably the most intriguing evil version of the Dark Knight wasn't technically Batman at all - but Mark Millar's Nemesis, published by Icon Comics (an imprint of Marvel).
Nemesis, you see, is an eccentric billionaire who likes dressing up in a costume and getting up to night-time antic. The key difference? Whereas Bats is fond of fighting crime and hiring inappropriately young sidekicks, Nemesis tends to go more for a president-kidnapping, mass-murdering, sibling-inseminating kind of vibe.
So, he's basically The Joker, but with Bruce Wayne's money. Which, predictably, doesn't end well for the comic's equivalent of Jim Gordon...
And, of course, there's arguably the greatest evil superhero of them all...
Jean Grey Becomes a Destroyer of Worlds
Yup, that's right - in X-Men: The Last Stand, Jean Grey kills a whole bunch of people before she's taken down at the movie's close. In the comics, she literally kills billions of people.
As in, she causes a star to go supernova, and it destroys an entire planet.
It wasn't, though, the last time that Marvel decided to temporarily transform one of its most legendary female superheroes into an evil version of themselves, but, to be honest, the less said about Susan Storm (aka The Invisible Woman)'s alternate, strangely S&M-fuelled identity 'Malice' the better...