In the Game of Thrones season premiere, the Hound (Rory McCann) had a vision that the Night King and his army are heading towards where the Wall meets the sea, leading some fans to wonder: why don't they just go around the Wall?
Given how close we are to the end of Game of Thrones, it's pretty safe to assume that at some point in the final two seasons, the White Walkers will make it into Westeros. But there is nothing saying that they have to do it by land. What there are, however, are some incredibly hilarious theories about why the White Walkers haven't tried to storm Westeros by sea. Let's break them down:
1. Skeletons can't swim: What is so great about this theory is that it's tackling a question about ice zombies with cold, hard science. In addition to the Night King's legions of White Walkers, a good portion of his forces are the skeletal wights. And according to Reddit user NyanBull, the reason you don't see the Night King lead his forces into water — for battle or travel — is because skeletons simply can't swim.
"As the body decays it releases gas and as the amount of gas inside the body decreases so does the ability to float in the water (if you want numbers while the density of the human body with air in its lungs is around about 1020 kg/m3 which is just enough to keep us floating, the density of the bare human skeleton is 1750 kg/m3). This means most of the wights would just sink in the water like stones," the user postulates.
But why does it matter if the wights sink to the bottom? It's not like they need to breathe, you wonder. Well, according to the user, the wights would likely be dragged out by the tides into deep water where the pressure would crush their brittle old bones. So you've heard it here, folks. Wights can't swim because skeletons can't swim.
2. White Walkers are allergic to salt. This theory not only covers the idea of the Night King's army swimming across, but also why they don't use their magical winter abilities to freeze the water and walk across. And it's simple, really: White Walkers are allergic to salt.
This idea does make sense given the popular lore that salt is a natural defense against the dead/undead (just think of how many times we've seen the Winchester brothers draw a salt circle on Supernatural). Reddit user BlueNinja5 also points out that Azor Ahai is supposed to be reborn amidst smoke (which comes from fire, one of the White Walkers' weaknesses) and — you guessed it — salt!
Because of this alleged natural aversion to salt, the White Walkers might not be able to spend long periods of time in salt water, which would make swimming or walking across sea near-to-impossible for them. Or, as the user succinctly put it, "TLDR The White Walkers are slugs."
3. The magical barrier continues in the water: This is the most likely answer, but also the least fun. It would have been insane of the people who built the Wall to only put the magical charms to keep the White Walkers out on the actual Wall. They probably extended the barrier out into the sea on either side of it as well, thus preventing them from popping in a boat and going around.
So if the White Walkers aren't heading towards Eastwatch-by-the-Sea to travel by water, why are they going there? There are mountains on the west coast once you cross south of the Wall and a fairly organized batch of soldiers at Castle Black towards the middle, so Eastwatch could be seen as the easiest access point through the Wall and into Westeros.
But more likely than not, the Wall is going to fall this season. We know the Night King's mark on Bran (Isaac Hempstead-Wright) was able to break the charms of the Three-Eyed Raven's magical Weirwood home, so there's a good chance that Bran already broke the Wall's magic when he crossed through. Plus, when you have a character like Jim Broadbent's archmaester definitively state that the Wall has always stood and always will stand, you know that the Wall is definitely going to fall. No one can be that blindly confident without being proven wrong. It's just a fact.
But you know what? Even if the Wall does fall and the White Walkers invade that way, it still doesn't prove that they aren't slugs.
Game of Thrones airs Sundays at 9/8c on HBO.