How 'Stranger Things' Season 2 Expands its Upside Down Universe

A closer look at the new creatures and rules established in the Netflix drama's second season.
Courtesy of Netflix

[Warning: This story contains full spoilers for season two of Netflix's Stranger Things.]

If you entered season two of Stranger Things expecting to learn the full extent of the Upside Down's nature, you almost certainly walked away disappointed — even if those expectations weren't exactly realistic to begin with.

But so we're all on the same page moving forward, the Duffer Brothers have explained to The Hollywood Reporter that the full breadth of the shadow dimension at the heart of their series won't ever make itself known. As Ross Duffer explains it, the show's relationship with just how much of the Upside Down it's willing to reveal very much remains "a balancing act."

"If you tell too much, it loses a little bit of that mystery," he says. "We obviously will shed more light on it moving forward, but we want to do it a little bit at a time. Even at the end, I don't think we're going to answer all of those questions, and I don't think we even necessarily need to." 

Duffer's explanation for why he doesn't feel Stranger Things needs to pull the curtain all the way back: "We're telling this story from the point of view of very human characters. There's no way they can ever truly fully understand this place. We have our Upside Down document which describes its rules and its mythology in quite a bit of detail, but I think we're just going to slowly parse that out, and maybe not even fully use all of it." 

With all of that said, it's not like season two doesn't expand upon the Upside Down at all. Whether through overt actions or subtle implications, the underworld of Stranger Things was definitely fleshed out over the course of these nine new episodes. Here's some of what we learned:

• There's a massive creature lurking in the Upside Down, one that makes the Demogorgon look like less than a cockroach. Mike (Finn Wolfhard), Lucas (Caleb McLaughlin) and Dustin (Gaten Matarazzo) dub the creature "the Mind Flayer," based on a Dungeons and Dragons villain with tentacles and psionic abilities. Is this the big bad boss of the Upside Down? Quite possibly — though an even more frightening prospect is that it's just one of many similar Mind Flayers strewn about the Upside Down, waiting to make their move on our world.

• The Mind Flayer is able to possess human beings, somehow infusing bits of its essence into unwitting hosts — Will Byes (Noah Schnapp), in the case of season two.

• Some like it hot. The Mind Flayer, according to Will, "likes it cold," in terms of its human host's body temperature. Spooky.

• Rather than focus on a single Demogorgon as in season one, Stranger Things season two introduces a bunch of new Demogorgonesque creatures: "Demodogs," as Dustin names them, four-legged creatures that emit "chittering" noises, according to the Netflix subtitles. They share a hive mind, and are all bound together at the apparent whim of the Mind Flayer.

• Season two shows the life cycle of a demodog, starting out as "pollywogs," as the kids name them, not unlike a larval tadpole. They look and feel like "boogers," according to Max (Sadie Sink). They become full-scale demodogs within a matter of a few days, based on how it times out with D'Artagnan, the pollywog Dustin briefly fosters at the start of season two.

• Much like the Mogwai of Gremlins, pollywogs don't respond well to light, and it's probably not a good idea to feed them after midnight either, given how much Dart grows immediately after eating nougat for the first time.

• The Upside Down is starting to grow into our world — or at least it was, before the portal underneath Hawkins Lab was fully destroyed by Eleven. (The Duffer Brothers have confirmed that Eleven was able to successfully demolish this connection between the two worlds.) Spore-filled roots, as big as tunnels, are growing underneath the sleepy Indiana town, filled with seemingly intelligent vines that produce a mucus of sorts. Both Dustin and Hopper are exposed to this slime during season two; worth keeping in mind whenever we get into season three.

• If there's a benefit from exposure to the Upside Down, it's this: "True Sight," an explanation for Will's apparent "now-memories," which allows him to see from the Mind Flayer's perspective. Is this a gift that's unique to Will, or is it something that develops for anyone who experiences prolonged contact with the Upside Down? And if so, could we see Dustin and Hopper experiencing "now memories" in season three?

• Finally, and most importantly: the Mind Flayer is still out there, last seen lurking above Hawkins in the thick of the Upside Down. What's its next move? Hard to say at the moment, though the Duffers offered one intriguing clue: the Mind Flayer walks away from season two "very much aware of the kids, and particularly Eleven. It had not encountered her and her powers until that final episode. Now, it knows that she's out there." What does it want with Eleven? We'll have to wait until season three to find out.

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