(Warning - the following could, if accurate, contain substantial plot SPOILERS for Captain America: Civil War. Or, it could just be an intriguing fan theory. It's really a roll of the dice at this point...)
Now, ever since it was first announced that William Hurt would be reprising his role as General Thaddeus 'Thunderbolt' Ross (from 2008's The Incredible Hulk) in 2016's Captain America: Civil War, speculation has raged as to just what his role within the plot will be. Y'see, while Ross' initial movie appearance stuck pretty close to his early comic book outings as a Hulk-hating military type whose daughter and Bruce Banner had a thing going, there's reason to believe that the general's upcoming appearance will include a pretty major piece of character development.
Specifically (and this is where those potentially massive plot SPOILERS kick in):
It Seems That General Ross Could Become the Red Hulk in Captain America: Civil War
After all, that's what very much happened in the comics...
Back in 2008, the Hulk comic book saw the arrival of a new and mysterious Red Hulk - a more aggressive, intelligent and heat-laser-wielding version of the hero, with a serious fondness for brutal violence.
Who, as it turned out, was actually General Ross, who had allowed himself to be transformed into that which he most hated - a Hulk - in order to finally defeat his green Nemesis. The only problem? His Hulk was a super confident, highly intelligent and distinctly murderous psychopath, who quickly went about removing any chance for Ross to return to his original human life.
Which, from the sounds of Hurt's recent comments about playing a General Ross "much different" from the one we saw in The Incredible Hulk, might just be something we're set to see in Captain America: Civil War.
As an intrepid Redditor, Koala_Guru, recently pointed out, however, there's a pretty solid chance that Ross wouldn't be able to transform into the Hulk all on his own. Instead, it's entirely possible that:
Tony Stark Could Be Responsible for Ross' Transformation into Red Hulk
Yup, that's right. The same Tony who was responsible for almost destroying the world by creating Ultron, to say nothing of all of those years where he was a lovable alcoholic arms dealer.
Koala_Guru's theory, suggests that:
Iron Man Could Well Be Losing the Civil War
Now, that could well be because Hulk has joined Cap's side - as has long been rumored for the film's latter stages - or because some of his key allies (The Vision, say) have deserted him; but either way, things may well not go too well for Tony, seeing as the majority of fans seem to be very much on team Cap.
If so, the speculation goes, Tony could team up with General Ross, who has presumably spent the last eight years trying to come up with a way to defeat the Hulk, and inadvertently come up with a way to become him instead.
Which Is Where Tony Comes in...
Or, rather, which is where Tony comes in, and presumably screws everything up. As Koala_Guru points out, you'd have to imagine that General Ross would have a cure for his hulkdom in place, before he'd be willing to dose himself up with gamma radiation and start running around smashing things.
But if Tony were to change the formula without telling anyone - which does seem very much a Tony kind of play - then Ross could suddenly find himself transformed into a very different, more intelligent and belligerent form of Hulk... who can't transform back to his human form.
Except, of course...
Tony Probably Wouldn't Tell Him Any of That
Y'know, what with inexplicably keeping important details from his teammates being kind of his thing and all (see, Ultron, Age of).
Instead, there's a pretty good chance that Tony would just send the - obviously government-affiliated - General Ross/Red Hulk into battle against Cap's Avengers, at which point...
We'd Get to See Red Hulk Fight the Hulk
Now, that could be because Hulk is already hanging around with Cap's gang, or it could come at the end of a successful Red Hulk attack on Cap's team (my personal thought: perhaps featuring a substantial injury to a newly defected Black Widow), which would thus prompt Banner (who would presumably have been skulking around keeping an eye on his dumb-ass friends) to join the fray on Cap's side.
Either way, we'd get to watch two Hulks pummel the snot out of one another for five minutes, which, when it comes to trumping that Hulkbuster sequence in Avengers: Age of Ultron, would pretty much do it.
Could It Actually Happen, Though?
Well, there are certainly some problems with the theory - including the fact that Hulk's seeming exclusion from Captain America: Civil War was assumed to be the result of the high cost of CGI, something that would be doubled down on by the inclusion of Red Hulk. What's more, there's seemingly already so much happening in the movie that adding an additional fifteen minute sub-plot about a general half the audience has forgotten about could be completely impractical.
That being said, though - it'd be pretty darned awesome if it did happen, so I'm not quite giving up hope just yet...
Nicely played, Koala_Guru. Nicely played...
What do you think, though?