There are many mysteries to be solved on Netflix's Stranger Things, but the one the might be the most pressing is figuring out exactly what the Upside Down is. The alternate dimension has been infiltrating the sleepy Indiana town of Hawkins since Stranger Things season 1, threatening the future and well-being of every character on the show.
The existence of the Upside Down has been a source of fascination and horror for nearly all of the characters on Stranger Things. Introduced in season 1, it became evident thanks to the disappearance of Will Byers (and Barb later on) that this alternate dimension is inhospitable to humans and should be avoided at all costs. In season 2, Hopper was clued into the possibility the Upside Down was seeping into his world, affecting plants and animals in the immediate area. As such, it was established that, should the Upside Down successfully bleed into our world, it would prove fatal for all human, plant, and animal life.
With two seasons under its belt and Stranger Things season 3 arriving on Netflix on July 4, figuring out more about what exactly the Upside Down is, how it operates, and even where it came from is going to be more important than ever. Understanding the ins and outs of this alternate dimension could mean figuring out just how the series will ultimately end.
What Is The Upside Down?
The alternate dimension that is the Upside Down has been a key location during Stranger Things' run. It looks like Earth, with similar landmarks and a similar layout, but it's completely devoid of human life. Furthermore, it's a safe bet that humans would be hard-pressed to survive there, which makes Will's season 1 arc, in which he was stuck in this world for a week, all the more intriguing.
The rules of physics seem to apply the same way they do on Earth, with regards to light, sound, temperature, and gravity. Certain locations, like the Hawkins' arcade and middle school, have appeared in the Upside Down. The buildings looked the same, except they're covered in web- and goo-like substances which seem to cover every part of this world. There's a darkness that permeates everything. It's full of shadowy, terrifying creatures who look like something out of a nightmare.
Things in the Upside Down appear to be in decay or disrepair, too. There are ash and spores of something floating around in the air, making for an environment that feels as claustrophobic as it does expansive. All of it makes for an unpleasant version of the world we know and one that would be horrifying to be stuck in.
What Created The Upside Down?
Stranger Things has yet to delve into the origins of this alternate dimension. The series begins shortly after it was discovered by accident but ongoing efforts inside Hawkins Labs to find out exactly how this dimension came to be have resulted in little to no information. However, Hawkins Lab has taken responsibility for opening up the Gate to the Upside Down itself, which was done after Eleven came into contact with the Demogorgon. Other than that, though, since there is a lack of English-speaking beings nor are there any written texts which exist in the Upside Down, it's difficult to get immediate answers from locals. The Upside Down creatures are able to inhabit the bodies of humans, allowing for communication between them and the humans, but no conversations, as seen on Stranger Things, have included a discussion about how this dimension came to be.
How To Get To (& From) The Upside Down
A few different methods of travel between the Upside Down and Earth have been shown on Stranger Things, but it's entirely possible other methods will be shown in season 3 or hinted at. In season 1, Eleven accidentally opened up the portal in Hawkins Labs. Her connection with the Demogorgon caused a portal to open up, allowing the scientists and Hawkins Labs to cautiously investigate the properties of this alternate dimension while the creatures from the Upside Down broke through, kidnapping locals and infiltrating the environment with its own awful flora and fauna. In the season 1 finale, it was discovered that in addition to going through the portal in Hawkins Labs, there were rifts all across Hawkins which had opened up, manifesting as membrane-like openings that required a person to break through them in order to go from one side to the other.
This was exhibited in the season 2 premiere when Eleven, who had been sucked into the Upside Down after trying to destroy a Demogorgon to save her friends, was pulled into the alternate dimension. She discovered one of these membrane-like portals in the Upside Down version of the middle school and could see and hear the Earth dimension through the membrane, easily breaking through to get back to her world. A similar portal also opened up in the woods outside Hawkins, which Nancy Wheeler went through in season 1 while she and Jonathan were investigating the existence of the Upside Down and the people working to cover it up. Toward the end of season 2, Hopper discovered a network of tunnels underneath Hawkins that were infiltrated by creatures from the Upside Down. The creatures had laid eggs while the flora and fauna of the dimension had fully spread across every surface. The tunnels led directly back to another Upside Down portal which Eleven proceeded to close (or so she thought) in the Stranger Things season 2 finale.
Upside Down Creatures
The scariest aspect of the Upside Down are its creatures. So far, two kinds of creatures have been introduced on Stranger Things: the Demogorgon (which evolve from Demodogs) and the Mind-Flayer, named by Mike, Dustin, and Lucas after Dungeons & Dragons beings.
In Stranger Things season 1, the Demogorgon is shown to be a predatory creature, with a Venus flytrap-like face which opens to consume its prey. It has entered into the Earth dimension looking for food and has been responsible for hunting and kidnapping Will and Barb. In season 2, the Mind-Flayer was introduced. The Mind-Flayer is the one able to make other creatures do its bidding, since it's believed that life in the Upside Down works as a hive mind, moving and operating as one entity. As such, the Mind-Flayer has been able to infiltrate the consciousness of humans like Will and Eleven in order to gain access to the human world and plan for an impending takeover our dimension, which will be the focus of Stranger Things season 3.