Get out your tin foil hats and your direwolf sigils, because it's time once again to get all up into some fan theories about Bran Stark.
Poor Bran. Little dude didn't ask to get pushed out of a window and then later become a psychic tree. Out of all of the Stark children, Bran might just have the weirdest destiny (or at least, he's tied with Arya... and Jon... you know what, I take it back, they're all pretty weird). He's not the only Stark to show signs of being a "warg," a person with the power to take over the minds of animals and even some people. But he's the only Stark so far who has taken that power to its limit: Bran seems to be able to see through the "eyes" of the weirwood trees, too.
And it seems like he can use those trees to go back in time.
In both the Song of Ice and Fire books and the HBO TV show, Bran is able to use the trees to glimpse images from the past. In the show, he's also able to change the past—or at least, he did something really weird to Hodor. It doesn't seem like he can cause alternate realities or change his own present by messing with the past, since Hodor was already stuck as "Hodor" when we first met him.
But it seems like Bran has already gone back in time and had an effect on certain moments in the past.
In the books, Bran is still hanging with the Three Eyed Crow (the Three Eyed Raven in the show), living under a big ol' tree and learning how to be a Magic Guy. We haven't seen the "incident" with Hodor yet. We've seen enough, though, to give a little credence to one of the wildest fan theories out there. Namely, the idea that Bran Stark built the Wall.
See, we know that a Bran Stark did actually build the Wall: Brandon the Builder, one of many, many Brandons in the history of House Stark. But could that Bran be our Bran? Did he go back in time and create the Wall to stop the White Walkers? Here's the evidence to support this time trippin' theory:
Firstly, Bran's name is Brandon. And Old Nan, his nurse, would frequently confuse him with previous Brandon Starks:
"She had lived so long, Mother had told him once, that all the Brandon Starks had become one person in her head."
Secondly, Brandon the Builder is said to have built the Wall in ancient times with the help of giants and the Children of the Forest. We already know that Bran is buddy-buddy with the Children of the Forest since he's living in their creepy tree cave.
Thirdly, Bran the Builder is referenced in the books as a young boy, who even as a child helped the kings of old design their castles.
"Some said the children of the forest helped him build it, shaping the stones with magic; others claimed that a small boy told him what he must do, a boy who would grow to be Bran the Builder."
And then there's a very vague hint from some of the bonus content for the HBO show, which depicts the legendary Bran the Builder being carried on a platform, much like how our Bran uses wheelchairs and sleds to get around.
Plus, the circumstances around the building of the Wall are entirely vague and shrouded in mystery. No one knows quite how the magic of the Wall works. None of us knew that GRRM was going to bust out time travel in the middle of his swords and sorcery series. It's entirely possible that our Bran will go back in time and play some part in the decision to build the Wall, or that he will hide something within the Wall for use as a later date.
But is he actually Bran the Builder? My guess is... maybe not.
Don't get me wrong, I think there's a chance that our Bran will be involved in the early days of the Wall. Clearly, there's some funny business going on with the magic of the Wall and the origin of the White Walkers that George R.R. Martin plans to reveal, if he ever finishes the dang series. But we've seen nothing (in the books, at least) to suggest that Bran can pop out of trees as a fully formed, visible boy. He seems to exist more as a spiritual presence when he visits the past.
Also... I know that Bran's a very advanced Spooky Boy for his age, but does he actually know anything about architecture?
I think it's far more likely that Bran might temporarily warg into one of the previous Brandon Starks, or perhaps speak to them through the weirwoods. Maybe our Bran will influence these other Brandons. Maybe our Bran will learn something about the Wall's beginning that will help him defeat (or join?!?) the White Walkers in the present.
Bran the Builder allegedly built both the Wall and the original castle of Winterfell, so perhaps a Bran-on-Bran hang sesh in the past could reveal some secrets about both buildings, secrets that could save the present-day Starks.
Whatever happens, let's all keep an eye (or three) on the Three Eyed Crow in training, and his time travel shenanigans.