…and the final monster at the mall began as a beach ball.

The creature effects in the Duffer Brothers’ Stranger Things 3 hit new levels this season, with several incarnations of an otherworldly monster brought to life in CG by the Netflix show’s visual effects crew.

Overseen by senior visual effects supervisor Paul Graff, amorphous blobs of goop that begin as rats and then ultimately form into a large multi-limbed Mind Flayer – realized by Rodeo FX – made up some of the most complicated VFX on the show.

befores & afters went behind the scenes with Graff, who tells us in his own words what informed the creature designs, how scenes were filmed, and what it took to pull off the dynamic visual effects shots.

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The caged rat becomes goop

Before rat designs, came monster designs: The very first point of departure was a meeting with the Duffers where they said, ‘The Thing is the thing this year.’ They wanted to honor or play with John Carpenter’s 1982 The Thing. It was a whole different ballgame from the more reticulated tornado-type Mind Flayer monster from last season. But the question was, how do we translate that into a heavy, wet, dripping, gory creature?

One thing was, it had tentacles, and we found that the tentacles, while they are really cool, it gets really busy when you animate it, and you have everything flying around. So, we decided that the tentacles are retractable. That was the first thing we figured out when we were playing with that design. And then, fairly quickly, we came to something that the Duffers approved. There was a concept drawing, the Duffers said; ‘That’s the one, that’s it!’

So, we had the monster, that was very defined. Then you have a bunch of chunks of goo that are floating around and it’s all influencing each other. They are basically blobs of meat of different kinds of gore. And then the third thing was this connective tissue. When the rat goes through the cage, for example, you can see it sticks to the cage and drags through it. So that was also how we connected all the creatures.

Evolution of a rat: So, the thing was, we knew this all had to evolve from the rat, not unlike what we did last season with the Pollywog. So the second expedition of the monster was exploding rats. And then, how do we turn these to goop, and how can we make monsters out of the goop?

The very first rat ever that had to be done in finished quality was when they’re at The Hawkins Post and they show a print, which is a a photo that Jonathan shot from in the cage. When we were shooting those scenes in the cage, there was just a silver ball in there. And for that photo, we wanted to have a CG rat. Now, we also tried a practical rat, and the CG rat won over the practical rat. So that was very encouraging. It felt like, ‘Well, looks like we got the rats figured out…’.

For the shot of the rat twitching and then becoming goo, we thought, let’s do first a version with the puppet rat, so that everybody has something to look at, and they can sort of get acquainted to their shot. The first take was a puppet, the second take was the silver ball. And then we had the cage in there and the cage out of there. Rodeo did the final shot.

The Tom/Bruce Monster

Creature design: I felt strongly that it was a good idea to go really asymmetrical. This Mind Flayer entity, this hive mind, is building himself a body out of bodies. But it’s not necessarily doing a perfect job at it. So there’s something really disgusting about a half-realized shape with extremities that are partially dead. He’s just dragging them behind.

And so, we felt, what if we build a monster that is completely out of whack, completely asymmetrical with one big side and one small? It’s like one big side with one giant limping limb. And then on the other side of it, it’s not symmetrical. It has a bunch of little legs. So, it’s kind of crawling all over, like a man on a cane.

Shiny metal helmet: We couldn’t really shoot any of the gore or the flying goop or body parts – none of it was ever on set. But what I did know is that I needed as much interactivity as I could get. It’s easier for the director, for the actors, for the camera department, to work, when they have an idea of what’s happening and what is where. All of these sequences were meticulously boarded, however. It’s like a comic strip, and you could see things that look very much like the final scene.

For the Tom/Bruce monster, I knew it was about human-size. I could make it a large human size, and I needed some kind of a stunt performer to stand in for the monster, to give us the energy. So I said to the stunt performer, ‘Well, I need somebody to wear this, who’s not shy wearing a spandex suit, and it’s not particularly sexy.’ And then we came up with the silver helmet, which was basically a giant reflector ball pass that’s already built into the shot.

The director, Uta Briesewitz, she literally directed him. It was really funny. 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. 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 reason we had the mirror helmet was, whenever shit hits the fan in Stranger Things, lights start flickering. And we need to replicate that on the CG character. I talked to the lighting crew on set and asked them if we could maybe have a loop. That the lights are always running in the same loop so you can build something that’s repetitive to match it. But that wasn’t possible. So I figured, well, what if we have a ball in the shot? Then you can read basically from the reflections of the ball where the lights are, and how intense they are. And that’s what we did.

Frankenstein’d together: The monster needed to have something that goes from a splat of gore and then forms into a monster. And it’s really two completely different types of CG that are blended together there by Rodeo. We have a creature that’s built, it has bones, it has a rig, it has physicality. And then you have this goop, and it’s really more like a simulation.

We wanted to have a nice organic mix of different material. When we see the big monster, if you closely examine it, you can see that it’s not really very similar. There’s a lot of areas made out of different matter, but sort of Frankenstein’d together.

We also thought, what if we have to make multiple versions of this monster in different scales, as it grows? And so I said I would like to have a kit, almost like a monster build kit, where we’re not completely tied down and have to build another monster. I’d rather build the monster in a way that it is scalable, and where we can change the way that extremities look.

The monster in the mall

Beach ball monster: We had to think, what is easy to get to, and be flexible, as a stand-in? For a 22 foot dinosaur-like creature, it’s a little hard. I was thinking maybe we can get one of those Cirque du Soleil groups with a giant dragon monster, but that was not really in the realm of what we could organize. But we did a mini-version of it, and that was a blow-up beach ball about three feet in diameter, mounted on a sound boom pole that was 20 feet long. So, that was about the size of the mouth of the monster.

And if you had a 20 foot tall pole, you could puppeteer it pretty well. It was not that heavy, and it could be lifted by one person and moved around. I had the supervisor from Rodeo come and puppeteer this ball according to the storyboards that we had. It was important for the eye line, to know where the face of the monster was going to be.

On fire(works): That sequence also has all those fireworks, and the problem there is that fireworks are basically the light source of the shot. You really have to try as best as you can to get something in there that is standing in for the light source. And so we had these masts with giant LED panels on top of them.

We knew the first one is green, then it goes purple, then it goes yellow, then it goes orange, et cetera. We went random with the colors, but for the first eight fireworks, we knew exactly when and what was showing, and what the color was. And so, we had these giant masts right in the middle of the shot that had to be erased. So, there was a lot of clean up, and there’s a lot of patching the CG mall over the practical mall, along with, of course, the CG creature.

This week at befores & afters is #vfxgeekoutweek. There’s a diverse set of stories tailor-made for VFX pros, aficionados and fans.