(Warning, potential Avengers: Age of Ultron and general MCU SPOILERS below)
Now, when it comes to Marvel fan theories, there have always been some that are stronger than others. For every correct prediction of just who that is cameo-ing behind Star-Lord in Guardians of the Galaxy, there are, sadly, inevitably always going to be three incorrect guesses. That, after all, is the nature of the speculation game.
There are some that come along, though, that seem so right, that make so much sense, and that fit the internal logic of the Marvel Cinematic Universe so absolutely, that it's difficult to imagine them being anything other than correct.
The theory below - recently conjured up by Lucas Siegel for Comicbook.com - is one of those theories.
And it goes, a little something, like this...
The Vision's Origin is About to Change...the Whole Marvel Universe
Yup, that's right. All of it.
To make sense of exactly why, though, we have to go back to The Vision's original comic-book origin, way back in 1968's The Avengers #57...
Now, after Ultron was created by Hank Pym, using his own brain patterns, the android set out to create his own robotic life-form, to use against his creator. Taking the brain-patterns of a minor Avengers villain known as Wonder Man (who later became a long-standing Avenger himself), Ultron created The Vision.
Usually described as a 'synthezoid,' The Vision was, unusually, given the ability to think, feel and love by a gem by Wonder Man's brain-patterns - but he was also given extraordinary powers by a gem stored in his forehead, known as a 'solar jewel.'
Now, the thing is...
Avengers: Age of Ultron Is Set to Completely Change The Vision's Origin Story
Specifically, since Hank Pym won't have created Ultron, and Wonder Man hasn't appeared in the MCU yet, it looks increasingly certain that The Vision's origin will actually take on a much more J.A.R.V.I.S-y vibe.
Now, sure, it's still possible that, say, Tony Stark will have frozen his father's beloved butler, Edwin Jarvis, and that Ultron will take his brain patterns and create The Vision. That being said, though, everything we know so far suggests a very different origin for the hero.
Which is where Siegel's theory kicks in:
That Gem in Vision's Forehead in the Most Recent Age of Ultron Trailer ISN'T a 'Solar Jewel'
Instead, he suggests, it's something far more important to the MCU: one of the Infinity Gems.
Specifically, the Soul Gem.
Now, traditionally, the Soul Gem has spent much of its time in the Marvel Universe on the forehead of Adam Warlock - who you may remember from that cocoon in Guardians of the Galaxy.
The thing is, though - he's not likely to turn up for another two years or so, and that leaves us with a whole lot of Avengers movies without a follow up to that long-running Infinity Gauntlet story-line that's been running since the first Avengers movie.
So, Siegel suggests, that stone on Vision's face? That's almost certainly one of the only two Infinity Gem's we haven't yet seen: The aforementioned Soul Gem.
Which, in the comics, has the power to capture souls - but could easily have its power altered for the movies, giving it the ability to grant an android the emotions and mind of a living being. Presumably, Ultron will have found it lying around somewhere - proof that checking behind the sofa is always worthwhile - and used it to create a weapon - who'll, you'd imagine, turns against his creator at some point.
All of which means...
Come Avengers: Infinity War, The Vision Would Be the Most Important Hero in the MCU
After all, if Vision is made into a living, thinking, loving synthezoid by that thar Infinity Gem, he and the Avengers are going to take issue with anyone coming along to try to take it away from him.
Which, seeing as he would need it in order to complete his dastardly, galaxy-wide plans, Thanos absolutely would.
So, that whole question of just how Thanos and The Avengers are going to end up battling one another? There'd suddenly be a simple and obvious answer: The Vision.
All of which makes such complete and utter sense to me that you can almost guarantee it won't make it into Avengers: Age of Ultron.
Either way, though - nicely played, Lucas Siegel. Nicely played...
What do you think, though? Is The Vision going to have his very own Infinity Gem? What else would that mean for the MCU - and Adam Warlock? And just when - and where - are we going to see the final Infinity Gem?