[Shawn Levy] You're seeing visual effects that look more and more photoreal. That's where things get really exciting. 

[Sadie Sink] This was not at all what it looked like on set. Props to the visual effects team, 'cause this is amazing. 

[Shawn Levy] Here's a little peak behind the curtain at the visual effects that helped bring this very satisfying sequence to life. 

Title Card: Behind the FX

[Shawn Levy] Max in the Mind Lair. 

[Clip] I've been waiting to hear those words. I am here, Max. To end your suffering.

No. 

Once and for all.

[grunts, pants] 

[Shawn Levy] So, in this sequence, Max has been following the reapparition of Billy.

[Sadie Sink] Obviously, she's grieving, but she's also feeling really guilty. Nobody knows that, but, of course, Vecna does.

[Shawn Levy] And she sees this kind of membrane of fog pulsating and this calling through that mist, only to find herself inside this kind of realm of Vecna's mind, the Mind Lair. 

Title Card: Creating the Mind Lair

[Sadie Sink] The set was pretty impressive. It was like a full-on platform that was built on a soundstage. 

[Clip] You're not really here. [pants]

[Shawn Levy] We always try to combine real art-department-constructed environments with these digital elements.

[Sadie Sink] It's all like the pillars in there and the ground was there and everything, but the sky, that was all just like a blue screen.

[Shawn Levy] The more you can practically build, the more you're helping your actor do their job, but you're also helping the audience with kind of an on-ramp to believability. She was standing in a real, rocky, bloody kind of pan.

[Sadie Sink] And I'm just remembering how slippery the ground was and how careful I had to walk on it. 

[Shawn Levy] One thing that people assume wasn't real but was is that winding staircase. That was very much there, and it allowed me to frame the expanse of the Mind Lair, and to also do shots behind that staircase, which is always useful if you can have a foreground element that actually exists. This shot here with blood dropping, that was a practical dummy with dripping glycerin. We augmented the gauntness of the face and the hollowing out of the eyes. But again, those were real dummies mounted in the practical set, which gave Sadie something to react to. 

[Sadie Sink] Chrissy's dead body didn't look as good as it looks in the finished product, but Vecna looks just as scary in real life as he does in the show.

[eerie music playing] 

Title Card: Max and Vecna’s Showdown 

[Clip] Would you like to join them? 

[Sadie Sink] This was the first scene that I ever had with Jamie, who plays Vecna, and my first time ever seeing him in his full prosthetic suit and everything. I mean, it's terrifying. Like, you'll be setting up for a different shot or something, and then he's in the corner, like, growling. And you're just like completely in it.

[grunts]

[Shawn Levy] Vecna is able to animate these kind of twisted, gnarled, flesh-like vines. We had Sadie running towards us, and then falling into a stunt pad.

[Sadie Sink] There was a rope tied to my ankle, and then it dragged me across the floor.

[man] Ready and pull! 

[Shawn Levy] We had about three guys on the end of a rope while we dragged the stunt Max on her belly and up against the pillar. 

But the vines, when I'm like…

[Clip] [groans] 

[Sadie Sink] None of that was there, so that was just like straining my arms and my neck to make it look like something was wrapped around them.

[man] Three, two, one, go!

[grunting and groaning]

[man] Right!

[man] Left!

Up!

[groans] 

[Shawn Levy] But we wanted the vines themselves to almost echo the flesh monster from season three.

[squelching] 

[Shawn Levy] To have this kind of churning, undulating life inside the meat, if you will. So you've got the meat of the vines, that was one stage of the process. Then you had rough animation, where it doesn't look like real-life texture. And then, slowly but surely, you're seeing visual effects that look more and more photoreal. And that's where things get really exciting because that started with a leap of faith, but you still get that excitement when you start watching a sequence that looks like it actually happened.

Title Card: Escaping the Mind Lair

[Clip] [Lucas] It's right here! I got it!

[frantic, overlapping chatter]

Okay, headphones!

Now!

[soft rock music plays]

[Shawn Levy] Once Vecna has Max pinned against this pillar and he's slowly kind of moving in for the kill, she has a vision. This kind of glimpse of her friends back in reality in that cemetery trying to wake her up from this Vecna-induced trance.

[Max grunting]

[Vecna groans]

[Shawn] She's running her ass off through this muddy pool, and she has to essentially be reacting to objects falling from the sky that weren't falling. So Sadie is bobbing and weaving and faking it, basically. It also helped that we had Sadie's stunt double take these awesome wipeouts into the muddy, bloody water. And so, it creates, again, a combination of digital effects and real energy. 

[Sadie Sink] It's definitely scary. And, like, it feels real. The stakes are really high. It was not the easiest set to film on. But, I mean, it looks amazing. 

[Shawn Levy] From artists, to visual effects engineers, to an entire cast and crew, it's deeply gratifying to tell stories that has both spectacle and emotionality that hits us where we live. Because, for me, my favorite kinds of storytelling are the ones that do both. 

[Sadie Sink] Thank you so much for watching Stranger Things 4, only on Netflix.