Marvel: 12 MCU Theories That Make Appalling Sense

9. The Return Of The Villains

The Theory

Thanos will use the united Infinity Stones in Infinity War to bring the Avengers' nightmares to live, "reviving" past villains destroyed by the Stones - namely Red Skull, Ronan and Ultron - to create a hellish union of baddies to help him take down the heroes.

The Evidence

It's all speculation at this point, but the comic book source suggests that the Stones are capable of trapping victims, rather than killing them, and strictly speaking, we didn't see any of those three key villains "die" in conventional terms.

And it actually makes sense: not only have we heard that there have been plans for villains to return in the past, but Thanos will probably need assistance once his Black Order inevitably fail to retrieve the Stones for him (he's already sign-posted that happening with his "fine, I'll do it myself" line in Ultron).

Perhaps it's wishful thinking, but the history of the Stones includes power reversal as a pretty big element, and if the theory that Thanos is going to use them to wipe out part of existence stands, we'll need some sort of foreshadowing to cleverly establish it.