The Stranger Things season 4 teaser trailer suggests the history of the Upside Down is being rewritten. The monsters of the Upside Down have consistently proved to be the most terrifying element of Netflix's Stranger Things, culminating in the introduction of the Mind Flayer, the monstrous creatures that dominate this alternate dimension and seek to conquer the Earth. Stranger Things has yet to explain the origin of the Upside Down, which seems so very similar to the Earth and yet disturbingly alien at the same time, and appears to be inimical to human life.
As seen in Stranger Things season 1, Eleven unwittingly opened a Gate to the Upside Down at Hawkins Lab when her powers flared out of control. Until now, everything that happened at Hawkins seemed to have spun out of that one act, with the Mind Flayer becoming aware of the Gate and attempting to force its way through. Intriguingly, Stranger Things season 3 revealed Russian Gate experiments in Kamchatka had been unsuccessful, with scientists concluding it was only possible to access the Upside Down from Hawkins. Most viewers understandably assumed this was because of Eleven; although she had sealed the original Gate, it had left lasting damage to the fabric of reality.
But the Stranger Things season 4 teaser trailer suggests that may well not be the case. Rather, it looks as though the Upside Down had broken through to the Earth decades before Dr. Brenner's experiments with Eleven went in an unexpected direction, and the lore of the entire series may well be about to change as a result.
The Stranger Things Season 4 Teaser Trailer Hints At The Upside Down... In The 1950s
The Stranger Things teaser trailer was focused mainly on introducing a new location that will be particularly important to season 4; the Creel house. Every season of Stranger Things has been a homage to different horror films, and now it's time for a haunted house – one that seems to be tied to the Upside Down. The opening shots in the Stranger Things season 4 teaser trailer showed what happened in the 1950s when the Creel family moved into their new Hawkins home. It didn't take long for them to begin experiencing strange events, with the lights flickering and the Creel daughter discovering a dead bunny rabbit left on the doorstep. Events build to a climax, with one shot of Victor Creel standing over the bodies of his two children. Teasers have suggested Victor Creel claimed some sort of demon possession, and he wound up committed to a psychiatric hospital.
Of course, all these events are quite easy for anyone familiar with Stranger Things to interpret. As seen in season 1, the flickering lights indicate a monster from the Upside Down tearing its way through to Earth somewhere close nearby, and the increasingly ominous blackouts suggest it was ultimately happening in the Creel house itself. The dead rabbit is probably a hint of a Demogorgon's hunting in the area around the Creel family home, and the murders were likely orchestrated by the Mind Flayer, which has the power to possess human minds and bend them to its will. Victor's accounts of demon possession likely mean the Mind Flayer's influence abated, perhaps indicating it only managed to influence the Earth for a brief period of time.
It's worth noting the events in the Creel house don't match up with anything seen in the 1980s; there's no hint of a Gate or a full-fledged invasion. Rather, the boundary between the dimensions in the Creel house seems to have simply been thinner and more vulnerable, allowing a Demogorgon and ultimately the Mind Flayer to affect the Earth. This actually makes sense because in Stranger Things season 1, the Demogorgon – an animal that operated on instinct – was a little too comfortable tearing through the dimensional barriers. It's possible the creatures have been taking advantage of weaknesses in the fabric of reality for decades, emerging on Earth to hunt before going back, and the opening of the Gate at Hawkins Lab simply made it easier to do this. The hints of the Mind Flayer's influence are more ominous, though, because, unlike the Demogorgon, this creature is intelligent enough to plan. However, it would undoubtedly have derived a vindictive pleasure from encouraging Victor Creel to murder his family; it is likely to have had other goals in mind as well.
The Upside Down Has Affected Hawkins Before Eleven
This subtly rewrites the lore of Stranger Things because it means Eleven was not responsible for creating the weakness in the fabric of reality that allowed the Upside Down to affect Hawkins. Instead, the weakness has always been there, and creatures have been tearing through it in order to hunt for decades. The combination of Eleven's powers and the thinner, more vulnerable dimensional boundary at Hawkins led to the creation of the first Gate, further weakening the boundaries of reality and allowing the Demogorgon to break through more easily. The interesting question is whether it was a coincidence Dr. Brenner built his lab at Hawkins or whether he was aware of reports of supernatural and demonic occurrences stretching back decades, leading him to conclude Hawkins was the perfect place to tap into the powers he believed lay inside selected children. The latter would be better because it would be less coincidental.
There are, however, disturbing implications from the tragedy at the Creel house. Previously, it had seemed as though the Mind Flayer only became aware of Earth when the first Gate was opened; now, it appears to have known about this world for decades, even figuring out ways to extend its influence into Hawkins and orchestrating at least one tragedy. The Mind Flayer is a Machiavellian entity, more intelligent than any Demogorgon, and it must have had an agenda. These plans changed when it discovered the Gates, but it will simply have gone back to its original scheme now the Gates have been closed.
Stranger Things season 4 is going global, with some of the kids leaving Hawkins and an arc involving Hopper's escape from a Russian gulag in the Kamchatka Peninsula. But it seems Hawkins is still important because the Mind-Flayer's influence continues even without Eleven and the Gates, and the remaining members of the Hawkins gang are stumbling on it. The lights are shown still flickering at the Creel house in the 1980s, but unlike Victor Creel, the kids know exactly what that means. Stranger Things season 4 looks set to continue the story of the Upside Down in the most unexpected way.