After years of speculation, Stranger Things Season 5 Volume 2 reveals that the Upside Down is not a separate dimension but a wormhole, an interdimensional bridge connecting Hawkins to the hostile realm known as the Abyss. This bridge, formed when Eleven made psychic contact with the Demogorgon in 1983, serves as a volatile passage filled with exotic matter. The show clarifies that all creatures, including Vecna and the Mind Flayer, originate from the Abyss, while the Upside Down is merely a corridor for their movement. This new understanding heightens the stakes for the series’ conclusion.
