How the 'Stranger Things' season 4 finale explains a key mystery about the Upside Down

How the 'Stranger Things' season 4 finale explains a key mystery about the Upside Down
·6 min read
A side by side image of Vecna (a skeletal villain) and a page of a D&D book about the Mind Flayer.
Vecna is linked to the Mind Flayer in "Stranger Things."Netflix
  • Warning: Major spoilers ahead for the season four finale of "Stranger Things."

  • In the ninth episode of "Stranger Things 4," Vecna reveals more about his time in the Upside Down.

  • He confirms how the Mind Flayer was controlled using his psionic powers.

The season four finale of "Stranger Things" widens our understanding of the mysterious dimension known as the Upside Down, as well as how all the evils that came from it were controlled by one person: Henry Creel.

Also known as Vecna and One ("001"), Henry has been behind every disastrous death in Hawkins since the start of the show. We've already laid this out in a timeline of the major events in "Stranger Things" so far, but now let's dive deeper into the details that were revealed about the Mind Flayer and Billy's season three possession in the finale.

Henry was banished to another dimension by Eleven, and there he found the mysterious particles that created the Mind Flayer

The source of Henry's powers is still unclear. He seems to have been born with them, and then wound up imprisoned by Dr. Martin Brenner and used for experiments.

In the season four finale, Henry monologues to Eleven about what happened to him after she used her powers to transport him into a new dimension. Henry says he was "somewhere new," and that he "became an explorer" of the dimension.

"I saw so many things," Henry told Eleven while recounting his exploration of the new realm. "And one day, I found the most extraordinary thing of all. Something that would change everything. I saw a means to realize my potential. To transcend my human form. To become the predator I was always born to be."

The Mind Flayer was never its own sentient being: It was a new physical manifestation of Henry himself.

A six-legged shadow monster towering over a man.
Henry and his Mind Flayer creation in the season four finale of "Stranger Things."Netflix

Henry had become interested in spiders at a young age. In episode seven, Henry described his "discovery" of the nest of black widows in his family home as the thing that gave him a "sense of purpose." He was fascinated and comforted by the spiders.

"Like me, they are solitary creatures and deeply misunderstood," Henry said in episode seven of season four. "They are gods of our world. The most important of all predators. They immobilize and prey on the weak, bringing balance and order to an unstable ecosystem."

So Henry took inspiration from the spiders, and created a shadowy monster that the Hawkins teens call the Mind Flayer.

Rewatching the show with all this in mind, it's neat to see the hints about the true motivating power behind the Demogorgon and Mind Flayer. For starters, the Demogorgon/Henry used telekinetic powers in the pilot episode when it unlocked Will's door. And in season two, the Dungeons and Dragon description for the Mind Flayer included "psionic" abilities — the same descriptor Murray once used for Eleven. In the first episode of season two, "Madmax," Murray tells Hopper a story he heard about a girl with "psionic abilities."

Henry used the Mind Flayer to find Eleven and 'bite' her — somehow absorbing her gate-opening abilities

In season two, Will was possessed by Henry via the Mind Flayer. Henry used Will to "spy" on Hawkins, learning more about what has been going on. But he never saw Eleven. She was away in season two when Will was possessed, and as soon as she returned, she helped close the Gate and seal off Henry's main access to Hawkins.

But a small piece of the Mind Flayer was left in Hawkins — the part that had been inside Will.

That piece survived, and in season three we saw how Henry was able to use it to form a physical body in Hawkins again, this time made from the exploded body parts and guts of rats and other residents. But now Eleven was prepared to fight. Henry came face to face with the powerful young girl once again.

At the time, the audience only saw Billy speaking on behalf of the giant spider-y Mind Flayer. But now you can rewatch the scene and better understand that he's highly interested in Eleven because it's really Henry behind those eyes.

In season three, episode six, "E Pluribus Unum," Eleven enters Billy's mind and is confronted by Henry.

A young man (Dacre Montgomery) with a mullet haircut looks tormented into the camera.
Dacre Montgomery played Billy in "Stranger Things."Netflix

"You shouldn't have looked for me," Henry said through Billy. "Because now I see you. Now we can all see you."

He continued: "All this time, we've been building it. We've been building it for you. All that work. All that pain. All of it for you. And now it's time, time to end it. And we're going to end you and when you are gone, we are going to end your friends. And then we are going to end everyone."

As he monologues to Eleven (a seemingly favorite pastime of Henry's), all the other possessed people in Hawkins made their way to the Mind Flayer's lair and exploded. Their corpses added to the physical form of the Mind Flayer, which then attacked Eleven and "bit" her.

This bite left a small piece of the Mind Flayer inside Eleven's leg. When she ripped it out of herself, her powers were lost.

Henry takes credit for this in the season four finale, saying he needed to find a way to open Gates between the Upside Down and Hawkins — something only Eleven had done.

"I sought a means to open my own doors," Henry said in the season four finale. "I sought your power. So don't you see? Once again, you have freed me."

So the Mind Flayer's "bite" in season three somehow helped Henry strengthen his own powers, enabling him to begin the murder spree we see in season four. With each psychic kill, a new gate opens, eventually leading to the final devastating scene where Hawkins is seemingly swallowed up by the Upside Down (something actor Noah Schnapp hinted could happen in an interview with Insider).

There are still a lot of unanswered questions about Henry and what will happen next

For starters, what is the material that Henry uses to create the Mind Flayer? Some kind of supernatural cloud? Energy particles? Secondly, why does the Upside Down look different when Henry first arrives there? The signature reddish glow is more yellow, and the landscape looks barren and rocky. How did Henry find Hawkins there? And why was the Hawkins Upside Down area stuck in 1983?

You can see all our burning questions here, and read a breakdown of all the best details you might have missed in "Stranger Things" season four here.

Read the original article on Insider