SA - Pop culture is again in the quickly decaying grasp of a shambling horde. For how many times zombies have appeared, they rarely have a real scientific reason to. Sometimes it’s a supernatural cause as in Dawn of the Dead. Other times it’s a generic “zombie virus” as in The Walking Dead (though at least we know how a “walker” bite works). In all the attempts to make the dead live again, science usually takes a back seat to the gore—at least until the latest popular iteration of zombies. The Last of Us—a new videogame touted as a masterpiece—has the most scientific explanation for zombies yet, because it uses zombies that actually exist.