The Upside Down is an alternate dimension existing in parallel to the human world. Most, if not all, flora and fauna present in the dimension are linked together in a hive mind-controlled by the Mind Flayer, essentially forming an enormous superorganism.
A key component of this hive mind was a species of humanoid predators, dubbed Demogorgons, which originated from the dimension.
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This all information is based on fiction stories from stranger things. It is not a real place and you can not visit it.
Upside Down Stranger Things
In November 1983, during an experiment hosted at Hawkins National Laboratory, a child test subject named Eleven made inter-dimensional contact with a Demogorgon and unintentionally opened the Gate.
Through this gateway, the Mind Flayer began using its dominion over the Upside Down to invade the town of Hawkins, spreading toxic biological matter presumably with the goal to eventually invade the entire Earth.
However, this plan was stopped when the Gate was closed, supposedly severing the dimension’s connection to Earth’s dimension.
The history of the Upside Down remains a mystery. Exactly how and why it came into existence, is unclear. However, its existence is heavily implied to be linked to the Mind Flayer.
In one of Hawkins National Laboratory’s experiments, a test subject labeled Eleven was immersed in a deep psychic state via sensory deprivation tank. She could observe people in different physical locations while in this frame of mind. Dr. Brenner sought to use this power to spy on enemy Russians.
While Eleven eavesdropped on a Russian spy, from within the Void, she accidentally encountered the Demogorgon. At Brenner’s request, Eleven made contact with the Demogorgon while it fed off a large, yellow egg.
At the moment contact was established, a gate between the two dimensions cracked open in the wall of the tank room, causing panic and confusion among the scientists.
Amidst the chaos, Eleven escaped from the lab and the Demogorgon set foot in the human world and proceeded to attack its first victims.
The Demogorgon moved through dimensions by creating temporary wounds in the fabric of time and space: It began harvesting the bodies of humans and animals, storing them in the Upside Down public library. Around the same time, Hawkins Lab began investigating the dimension and discovering exactly what it contained.
At one point, Nancy Wheeler entered the Upside Down through a temporary portal in the base of a tree. She realized it was dangerous to stay in the dimension, quickly leaving before the Monster could find her.
Although Will Byers was taken into the Upside Down by the Demogorgon, he managed to evade capture for several days. During that time, he attempted to communicate with his mother after he realized he could manipulate electricity in his home dimension.
On one occasion Will found a temporary portal in the wall, briefly talking to his mother directly through it before it resealed. The Demogorgon eventually found him inside Castle Byers and took him to the library.
Hopper and Joyce later entered the Upside Down via the Gate, eventually finding Will attached to a tendril extending down his throat, which they immediately removed. After Will was resuscitated, the three returned to their home dimension, presumably back through the Gate.
At the Hawkins Middle School, to protect Mike, Dustin, and Lucas, Eleven used all her remaining strength to disintegrate the Demogorgon and vanished away.
However, it was revealed that she was actually transported back to the Upside Down. Eleven later escaped the Upside Down by enlarging a portal to the real world.
1983 – 1984
One month later, everything had seemingly returned to normal in Hawkins. However, Will’s time in the Upside Down had severely affected him. He began to see visions of the Upside Down temporarily flicker into existence around him.
By 1984, the Hawkins Laboratory staff was changed from its previous workers, with Dr. Sam Owens taking over as Head of Operations. After finding out about his episodes, Joyce began taking Will to the lab where he’d be looked over by Owens.
Meanwhile, the lab continued to study the still open Gate and the Upside Down, placing a probe-like machine within the dimension, presumably to gather data.
In an attempt to keep the growth under control, they began to periodically burn the vines and tendrils extending from the Gate. Despite these attempts, the Gate eventually grew to an enormous size, extending far beneath the lab and forming a series of tunnels.
The word about the Upside Down spread to Russia where the Soviets decided to access their own way to the Upside Down. By June 28, 1984, Soviet scientist invented a machine that was capable of tearing through time and space that could open a Gate to the Upside Down.
However, when activating the machine, it exploded, killing a bunch of scientists after a Gate was partially opened before it closed. Many more of these machines were built in Russia, but they ended up with the same results as the first machine.
Will have another Episode
On the evening of October 29, as Will was at the Palace with his friends, he began having another episode. He walked out the door and witnessed what appeared to be a red electrical storm.
The following morning, Hopper was called to Merrill’s farm to investigate a strange rot that had decimated the entirety of the pumpkin patch. During his appointment at the lab later that day, Will told Owens about his vision. Will told him that he believes an evil force wants to kill everyone.
Instead of taking heed of this warning, Owens told Joyce and Hopper that the increased number of Will’s visions was simply caused by the “Anniversary Effect”.
That night, Will experienced another episode while in his living room, witnessing the door swing open to reveal the Upside Down. He stepped outside, seeing the silhouette of a massive spider-like creature.
Hopper continued his investigation of the rotten crops and discovered that the rot had begun to spread to the nearby trees. That night, as Mike, Lucas, Dustin, Max, and Will were trick-or-treating, Will again had another vision of the Upside Down. He watched as the massive shadow monster ascended into the sky and began pursuing him.
When returning home that night, Dustin found a small pollywog-like creature in his trashcan, naming it D’Artagnan. When Dustin brought Dart to school the next day, Will believed it to originate from the Upside Down due to its resemblance to the slug he had coughed up a year before. After warning his friends, they took Dart to the AV room where they witnessed it grow a pair of hind legs.
Mike tried to attack Dart, causing it to flee and run loose throughout the school. Will eventually found it in a bathroom; Dart screeched at him, causing Will to run away.
As he ran through the halls, he suddenly began having another episode, being transported to the alternate version of the school. Running outside to the field, he was again met by the gigantic shadow monster.
Instead of running, Will tried screaming at the monster to go away. The shadow monster then engulfed Will in one of his tornado-like appendages, allowing a part of himself to latch onto Will.
From that point on, Will gradually became possessed by the shadow monster. His body temperature dropped and he developed an aversion to heat. He also began experiencing what he called “now-memories”, where he could see and know what the shadow monster did.
In order to better explain his now-memories, Joyce asked Will to draw what he saw. He began frantically drawing what at first appeared to be random scribbles, but Joyce and Hopper soon realized that the drawings were all connected. After assembling the drawings in the correct order, they discovered the drawings depicted a strange maze-like pattern.
Believing the drawings to depict vines, Hopper went back to the pumpkin patch. By digging into the earth, Hopper discovered the existence of the underground tunnels, overgrown with biological matter from the Upside Down. While traversing the tunnels, Hopper became entrapped in vines, unable to escape.
Will learned of his predicament through his connection with the shadow monster, and with the help of Bob Newby, they were able to pinpoint his location within the tunnels. After Joyce and Bob successfully freed Hopper, soldiers from the lab arrived and urged them to leave. As the soldiers began burning the tunnels, Will suddenly collapsed and began convulsing on the ground.
Will was taken to the lab where he was quickly sedated. When Will awoke, he could not remember Owens, Bob, or Hopper, and was barely able to remember Mike.
In a test involving a severed vine from the Upside Down, Owens asked if Will could feel anything as another scientist used a blowtorch to burn the vine. Through this, they determined that Will had some sort of “virus” that connected him to all other infected hosts in a hive intelligence.
Dustin soon discovered that Dart was actually a baby Demogorgon and trapped it in the storm cellar.
He then enlisted Steve’s help in dealing with it. However, when they entered the cellar, they discovered that not only had Dart molted again, but it had also escaped through a tunnel it had dug in the earth.
Dustin and Steve, along with Lucas and Max, came up with a plan to lure Dart to the Junkyard using raw meat. While this plan succeeded, they had also managed to attract several other members of Dart’s species. While the pack was attacking the bus, they suddenly stopped and began heading towards the lab.
Claiming he knew of a way to beat the shadow monster, Will pointed out a location in the tunnels, saying “he doesn’t want me to see there.” As the soldiers entered the tunnels, Will revealed that the shadow monster had forced him to deceive them.
The soldiers were ambushed and killed by a pack of Demodogs. Shortly after, Demodogs began invading the lab. While the group was escaping the lab, Bob was tackled and killed by several Demodogs. Everyone else, excluding Owens who had stayed behind, managed to escape the lab.
While speculating the shadow monster’s weakness, Lucas, Mike, Dustin, and Max theorized that if they destroyed the monster, they would also destroy the monster’s army.
When they realized that the shadow monster controlled everything in a hive mind, they compared it to the Mind Flayer, a monster from Dungeons & Dragons that similarly controls the minds of its victims. The boys’ D&D manual also stated that the Mind Flayer’s goal was to spread and take over other dimensions, making them speculate that the shadow monster wanted to do the same. The group then planned to interrogate Will to find the shadow monster’s weakness.
After making the backyard shed unrecognizable, they attempted to interrogate Will. While the Mind Flayer had taken over a majority of Will’s mind and body, a part of Will managed to subconsciously signal to them in Morse code.
Deciphering his message, they discovered the way to stop the Mind Flayer: closing the Gate. Soon after, the phone in the Byers’ kitchen rang, giving away their location. A pack of Demodogs quickly surrounded the house. Before they could attack, Eleven arrived and eradicated them.
After taking Will to Hopper’s cabin, Joyce, Nancy, and Jonathan restrained him, surrounding him with numerous heaters. This eventually caused the piece of the Mind Flayer possessing Will to be expelled from his body.
Hopper guided Eleven through the lab to the Gate, so that she may finally close it for good. Drawing on all her strength and pain, Eleven successfully used her powers to seal the space-time rift, presumably cutting off the Mind Flayer from Earth.
On December 15, during the Snow Ball, the Mind Flayer loomed over the Upside Down version of Hawkins Middle School. Also, the part of The Mind Flayer that was inside Will Byers still remained in the human world and was in a state of hibernation.
The Russian government realized that the location of their machine, the Key, was only part of their problem in trying to gain access to the Upside Down. Knowing that the Gate was open in Hawkins, Indiana before its closure, the Soviets decided to secretly go to America and build a Key in Hawkins as the fabric of time and space was still healing.
Through Starcourt Industries, the Soviets made dealings with the Mayor of Hawkins, Larry Kline to buying up property in East Hawkins. To operate the Key, the Russians began construction on Starcourt Mall where it would serve as a front with their base underneath the mall as they built a Key machine.
Upside Down Connection
The connection between the Upside Down and its opposite dimension was seemingly established when Eleven made contact with the Demogorgon using her psychic abilities, causing a gate to rip open in Hawkins National Laboratory.
It contains the same locations and infrastructure as the human world, but it is much darker, colder, and obscured by an omnipresent fog while ash-like spores drift through the air. It is devoid of human life, instead of being overgrown with ropy, root-like tendrils and biological membranes covering practically every surface.
There is little proven knowledge concerning the Upside Down, as it remains shrouded in mystery. In spite of this, the dimension possesses a few observable properties and characteristics.
Such as, light, gravity, and sound appear to function the same way as in the regular world. Furthermore, noise and sound originating from Hawkins are somehow faintly audible in the Upside Down, almost like an echo effect.
This allows Will to hear Joyce’s voice when he is trapped in the Upside Down; similarly, Joyce hears Jonathan’s voice when she visits the dimension’s version of her house.
However, sound from the Upside Down is not seemingly audible in Hawkins, unless there is a nearby inter-dimensional portal which it can pass through.
This is demonstrated by the fact that Jonathan and Nancy were able to talk to each other when they were near one such portal, despite being in separate dimensions.
According to the scientists of Hawkins Lab, the atmosphere was toxic to humans, hence why they wore hazmat suits to enter the dimension.
However, it seems the atmosphere is only damaging after prolonged exposure, as Nancy entered for a brief moment and showed no signs of damage, whereas Will was exposed to the air for a week and became very sick.
This toxicity appears to also extend to the dimension’s flora and fauna. When a series of subterranean tunnels extending from the Upside Down began to spread and grow beneath Hawkins, they caused several farmers’ crops to rot overnight.
Trees in the woodlands in close proximity to the affected farms were also observed to have the same rot. When Hopper explored the aforementioned tunnels, he was sprayed in the face by a growth on the ceiling, causing him to lose consciousness almost immediately, and upon waking up, vomit a black substance.
The Upside Down contains no life recognizable to humans beyond plants and trees, instead of harboring its own unique biology and ecosystem.
Biological growth of various kinds, such as tendrils and flesh-like membranes, are prevalent across the dimension’s version of Hawkins, permeating and covering most surfaces. These life forms appear to grow and spread in a similar fashion to fungi or plant life.
The Duffers have revealed that they have a 30-page document that intricately explains the Upside Down. While the lack of what has been revealed regarding the dimension’s mythology is due in part to time constraints, they have also noted to intentionally keep details scarce.
In order to preserve the mystery and horror, they deliberately keep most knowledge of the Upside Down from the point of view of the characters. Matt explained that “it’s scarier when you don’t fully understand what’s happening.”
What is revealed also depends on the story. For instance, the Duffers wanted the first season to have a simple drive, focusing mostly on Will’s disappearance, while hinting at the larger mythology behind the Gate and the Upside Down.
However, they are sure to not let logic dictate all of their decisions. As long as it’s not cheating the audience and feels like it belongs in their world, the Duffers often use ideas that simply excite them. Explaining any gaps in the mythology that arises is not their greatest concern.
Facts about Upside Down Stranger Things
- Joyce‘s way of communicating with Will through the lights and hearing him in the walls of the house is an allusion to the 1982 horror film Poltergeist, in which young Carol Anne goes missing in another dimension and can be heard through the TV and walls. Also similar to Joyce, Carol Anne’s mother ended up entering the other dimension to save her child.
- In the original script, the Upside Down was referred to as the Nether (although Upside Down was still the name the characters used in dialogue). The popularity of the in-universe nickname on the set led to it being referred to almost exclusively by that name instead.
- Many fan theories suggest that Jim Hopper is currently in the Upside Down. This would mean that he would have been sucked in through the gate during the destruction of the key.