The first being to enter the Upside Down was Henry Creel (001/Vecna), accidentally banished there by Eleven in 1979, effectively creating the dark dimension as a gateway for the Mind Flayer, though the Demogorgon was the first to physically cross into Hawkins in 1983 when Eleven opened the main gate.
The Upside Down was created on November 6, 1983, when Eleven made psychic contact with the Demogorgon. The Upside Down's origins are tied to the Abyss, an alternate dimension and the apparent home of the Mind Flayer entity, a race of humanoid predators and other lifeforms.
The Mothergate was unintentionally opened by Eleven on November 6, 1983; Eleven was directed by Dr. Brenner to make psychic contact with the Demogorgon, an action which tore apart the fabric of typical reality, forming a rift in the wall connecting to the Upside Down.
The Upside Down is a dark mirror of Hawkins. It formed when Eleven made interdimensional contact with the Demogorgon in her mind space, the void in Season One. That moment created the Mother Gate, which is why it's stuck in 1983, not 1979, when she banished Henry.
Cuz we were told that 11 accidentally created the upside down when she made contact with this Demogorgan in her mind space when she was at the Hawkins Lab in a bath.
However, after he revealed his true nature as a misanthropic, nihilistic, and genocidal psychopath, Eleven overpowered Henry and sent him to the Upside Down, where he was gradually disfigured by its abnormal lightning and toxic atmosphere, transforming him into the being known as Vecna.
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Yes, Dart (D'Artagnan) is a baby Demogorgon, specifically an adolescent stage called a "Demodog," which Dustin Henderson found and raised in Stranger Things Season 2; he's essentially a younger, less aggressive version of the main monsters from Season 1, evolving from a pollywog-like creature into a four-legged, predatory form.
When Nancy is talking with Mrs. Holland on the phone, she tells her a lie about Barb being at the library. Ironically, this would turn out to be true, as her corpse was found in the Upside Down version of the library.
Ross Duffer said Eleven's death, or disappearance, was integral to the story ending. Eleven represents childhood — and the finale is all about the kids of “Stranger Things” growing up.
Martin Brenner was intrigued by the creature, repeating the experiment on November 6, 1983. This time, Brenner ordered Eleven to make contact. As Eleven psychically approached the Monster, she could see it feeding off an otherworldly egg. With great hesitancy, she made contact.
Soviet scientists developed "the Key", an experimental technology designed to penetrate the space-time barrier and create a gate to the Upside Down.
Where did Eleven send Henry after their showdown in the Rainbow Room? Eleven banished Henry to the Abyss, not the Upside Down, after eviscerating him in the Rainbow Room in a flashback in Season 4. As Dustin explains, Henry would have “remained lost” had Dr. Brenner not forced Eleven to search for him.
The first known gate was created after Eleven overpowered One in a psychic duel on September 8, 1979; somehow, a temporary gate opened in the wall of Hawkins Lab's Rainbow Room, pulling One into a realm beyond the human world.
1. The image projected onto the back of our eyes is upside down. Our brain decodes this image so that we perceive it the right way up.
The Upside Down in Stranger Things was originally called "the Nether," but the show wisely switched to its iconic name, enhancing its allure. Sticking to "the Nether" would have been a bad decision, as "the Upside Down" perfectly captures its eerie and unique essence.
While Nancy Wheeler loses her virginity to Steve Harrington, Barb Holland awakens in a waterless, dark version of Steve's pool, every surface covered in fleshy black vines.
In November 1983, he vanishes somewhere near "Mirkwood" after encountering a monster that escaped through a rift to the "Upside Down", an alternate dimension discovered by the Hawkins Laboratory scientists. He is presumed dead, and a funeral is held for him.
Barb didn't go missing without a trace though, we saw her gory and very dead corpse.
Noah Schnapp hails Will Byers as "one of the best queer characters," as Jamie Campbell Bower and the Duffer brothers reflect on the importance of his coming out scene in the penultimate 'Stranger Things' episode.
So, in conclusion, the Mind Flayer possesses the Demogorgon, whom was 001, proving that the Mind Flayer cannot be 001. This explains how Brenner survived, how the Demodogs were created, and how and why the other test subjects of Brenner's escaped.
In Stranger Things, several characters say the F-word, including Will Byers, Billy Hargrove, and most notably, Joyce Byers (Winona Ryder) in a significant Season 4 moment when confronting Vecna, delivering a rare and impactful "You f***ed with the wrong family". Other instances come from characters like Billy (often possessed), and even faint or muffled uses have been noted from others like Jonathan.
The "worst" Stranger Things episode is subjective, but Season 2's "The Lost Sister" (Chapter Seven) and Season 5's "The Bridge" (Chapter Seven) are consistently cited as the lowest-rated by fans and critics, with "The Lost Sister" often criticized for its slow pace and spinoff potential, while "The Bridge" drew mixed reactions for its pacing and Will's storyline.
While "most loved" is subjective, Steve Harrington and Eleven consistently rank as top fan favorites, with Steve praised for his epic character growth from bully to "babysitter," and Eleven for being the show's central, powerful hero, though Dustin Henderson, Jim Hopper, and the tragic Eddie Munson are also extremely popular. Different polls often place Steve or Eleven at the very top, depending on the audience demographics and specific season focus, with fan-favorite moments often highlighting Steve's comedic timing and selfless acts, and Eleven's strength and vulnerability.
Yes, Dr. Martin Brenner died at the end of Stranger Things Season 4, shot by a helicopter sniper in the Nevada desert after his plan to help Eleven failed, seemingly marking a definitive end to his character, despite previous instances where his survival was hinted at.