Watch M. Night Shyamalan, Sarah Paulson, and James McAvoy debunk Glass fan theories

Glass, the final film in M. Night Shyamalan's trilogy of superhero stories that began nearly two decades with Unbreakable, is finally in theaters, so we can all go experience its various twists and revelations for ourselves. Before Glass arrived, though, moviegoers had two years to sit back and analyze Unbreakable and its surprise sequel, Split, looking for clues about what the third film might hold.

Naturally, this spawned quite a few fan theories, and now Shyamalan himself and two of Glass' stars are here to pick those apart. 

Shyamalan joined James McAvoy (who plays Kevin/The Horde, along with nearly two-dozen different personalities throughout the film) and Sarah Paulson (Dr. Ellie Staple) for Vanity Fair's ongoing video series in which creators and stars of popular genre franchises unpack fan theories delivered via Reddit, and unsurprisingly, there are some ambitious ideas at work here. The theories were, of course, all developed before the film was released, and Shyamalan and company aren't throwing out any Glass spoilers, but given what we know now about the film, it's very interesting to see where people thought this was going. 

Among the theories: Everything — Glass, Split, and Unbreakable — is happening inside the head of a single person, who could be named Elijah... or Kevin. There's also the theory that David from Unbreakable is actually Malcolm from The Sixth Sense, or rather that they're both the same personality who can inhabit multiple bodies over a period of centuries, and also be a ghost sometimes.

Then there's the idea Shyamalan himself seemed most taken with: That Glass and Signs take place in the same universe, and that the superpowered characters have somehow been infected with alien DNA, which explains (among other things, supposedly) David's aversion to water. 

For more theories, including the possible hidden superpowers of Casey (Anya Taylor-Joy) and Joseph (Spencer Treat Clark), check out the video above. What weird theories did you have about Glass before you saw the film in theaters?