How Stranger Things' Mind Flayer Came To Life

When the Mind Flayer debuted during Stranger Things' third season, it looked like something straight out of a nightmare. On screen, the dripping, multi-legged creature draws part of its power from the pulverized bones and blood of its victims. On set, however, season 3's main antagonist materialized through a VFX process that, when you see it, feels hilariously similar to a villain unmasking on Scooby-Doo.

A tweet posted by Netflix revealed that the thing haunting Hawkins was actually just a man in a red spandex bodysuit and a big, shiny helmet. Behind the scenes footage that demonstrated this dichotomy emerged after season 3 dropped in an Instagram video posted by the series' cinematographer, Tim Ives. In the brief clip, a stunt actor donning the red suit and what Ives calls a "Kazoo helmet" is seen crashing and yelling down a hospital hallway. Most fans will recognize this as the chase scene in episode 6, "El Pluribus Unum," in which Nancy (Natalia Dyer) works to outrun the Mind Flayer as Jonathan (Charlie Heaton) attempts to distract it.

Stranger Things senior visual effects supervisor Paul Graff confirmed to befores & afters that shooting the sequence was as funny as watching it. "Everything was quiet. The lights go off, the lights go on, and there's this guy who looks like he's from some kind of Russian evil fantasy," Graff said. "He's there spreading his arms and screaming at the top of his lungs and then just charging down the hallway. Still one of my favorite moments."

The yelling might be explained as a way to help the actors get more into the scene, but what exactly was with that helmet? According to Ives and Graff, it ensured the flickering light effect could be replicated on the CG character. Funnily enough, that wasn't the only shiny sphere the show used to bring the Mind Flayer to life.

Believe it or not, the suit and helmet behind that scene may be outdone by a prop fitting season 3's summer theme. While Stranger Things stars Heaton and Dyer worked with a stunt actor, other cast members were facing off with a shiny beach ball. In a tweet captioned "We had a ball on set," the Stranger Things writers room shared a video of the summer essential as a stand-in for the monster. That's a far cry from the towering and toothy blob viewers saw on screen, which Graff said was inspired by another entity with origins in 1980s horror. 

If the Mind Flayer looked like a creature you'd already seen, and that creature was the alien from The Thing, you have a good eye. Graff said that Stranger Things creators Matt and Ross Duffer came to him early on with the idea that this year's big antagonist would "honor or play with" John Carpenter's creation. "We wanted to do something fleshy this year and something with teeth and wet and heavy," Graff told befores & afters. "It was a whole different ball game from the more reticulated tornado-type Mind Flayer monster from [season 2]."

With that monstrous inspiration in mind, the trio settled on several design elements that would give the Mind Flayer its gory look. That included tentacles, which they made retractable to avoid "everything flying around." There was also the being's actual composition, which they ultimately settled on being "chunks of goo" and "blobs of meat" that are floating and connected through a sticky tissue.

These moving parts helped the Duffers translate their concept of a wet, dripping, heavy creature into the Mind Flayer we all know and love.

The Duffers told Graff early on that Carpenter's The Thing was going to be "the thing" for season 3, but it wasn't the only part of the malevolent entity's inspiration. In the series, the protagonists used their knowledge of Dungeon & Dragons to figure out how the Mind Flayer, then a shadow monster, worked. On the official Stranger Things season 3 podcast, writer Paul Dichter revealed that the kids' decision to name the supernatural being tormenting Will Beyers after an actual D&D character was a mirror of what had happened in the writers' room. "When we came across the Mind Flayer in Dungeons and Dragons mythology, it was such a shocking discovery," Dichter said.

The Duffers also drew inspiration from something to which everyone can relate: Puberty. On the third episode of Netflix's Behind the Scenes: Stranger Things 3 podcast, writer Kate Trefry detailed why they chose to have the Mind Flayer's metamorphosis — particularly its gross composition — mirror their preteens' coming of age. According to Trefry, "Puberty is disgusting, and it's awful," and the writing team wanted to "lean into that as much as we possibly can."

"I always thought [caterpillars] go into their cocoon, they grow wings, and they come out," she said. "But that's not what happens at all. When a caterpillar builds its chrysalis, its whole body dissolves into goo, and then the DNA gets rearranged into a completely different animal, and that animal is what gets reborn."

For Trefry, the butterfly analogy perfectly encapsulates why the Stranger Things team chose to make its antagonist a "sticky, gross, toothy weird" creature. "It's that moment of, everybody is turned to jelly, and we're waiting on the edge of our seats to see what they become."