SPOILER ALERT: This article contains spoilers for “Clayface,” now playing in theaters.

Batman fans will have to wait patiently for the next installment in Matt Reeves and Robert Pattinson’s Caped Crusader saga, but they can get a peek at the rebooted DC Universe’s Gotham City in “Clayface.”

“Clayface” is an R-rated body horror that follows the shape-shifting Batman foe. It blends a supervillain origin story with some stomach-churning scares and comes from horror veterans including director James Watkins and a story by Mike Flanagan. Tom Rhys Harries plays Matt Hagen, an A-list actor who is brutally disfigured by a gangster. With his face ripped up and his career destroyed, Matt turns to an experimental procedure from Dr. Caitlyn Corr (Naomi Ackie), which heals him — but slowly turns him into a clay-covered monster.

Matt’s blood cells gain the ability to transform and instantly reshape his body into someone else, such as Corr or the gangster who disfigured him or even his own father (played in a quick cameo by Aaron Paul). He loses control of his own body and sanity as these newfound shape-shifting powers help him enact bloody revenge on the mob who ruined his life. In the end, Matt kills everybody who wronged him (plus several innocent people), and is forced to live as a reclusive mud monster in the sewers.

Clayface has appeared in many Batman comics through the years, and he’s a classic villain who’s made the crossover into animated shows and video games. This version of him has also technically already appeared in the rebooted DC Universe in James Gunn’s animated series “Creature Commandos,” but now the monster gets his own origin story and live-action debut. The movie also gives the first look at Batman’s hometown of Gotham City in the new DC Universe. Gunn’s “Superman” kicked things off in Metropolis last year, but now another one of DC’s most famous cities gets unveiled in “Clayface.”

With Variety, Watkins explains finding the final Clayface monster look, recruiting Paul for his cameo and creating Gotham City.

The Clayface name has been used by several villains in Batman comics. How did you land on the Matt Hagen version instead of the first iteration, Basil Karlo?

It was really landed by Mike Flanagan and the script. I read all of them, Basil Karlo and all, afterward because there are bits and bobs that are kind of cherry-picked from all over the place. But the key journey, and that’s what Mike had chosen, was the Matt Hagen version. If you’d have gone with Basil Karlo, it’s a little bit too gothic or too hard to do in such a modern idiom. The Matt Hagen is a more relatable version. Whether it’s Basil Karlo and Boris Karloff, there are all those characters that it’s referring back to in the Golden Age of Hollywood, that sort of thing. This is something that can sit in our contemporary time. Our Gotham is not entirely contemporary. It slightly steals from a few different genres. We wanted it to be slightly timeless, but it can play as contemporary.

This is the first time we’re seeing Gotham in the rebooted DC Universe. Did you have a specific year or time you wanted to set the world in?

We deliberately wanted it to be a bit muddy. James Price, our brilliant production designer, and I talked a lot about creating the sense of the world, and we wanted it to feel like a character in the movie. We wanted this oppressive world where the buildings really dominate. We looked at a lot of 1930s German expressionist cinema with huge dominant buildings and the odd angles and the noir-ish shadows. We also looked at street photography from New York from the ’70s, the ’80s and the ’90s. It was all before New York had been cleaned up. The lighting is different. It’s a lot of neon. There’s a lot of practical lighting. There’s a lot of dirt and eccentricity on the street. We wanted to definitely frame Gotham as a contrast to Coast City, with the colors, the bright sunshine, the sky, the sea. You see verdant greens and textures and stuff like that, which you don’t really see in Gotham. You barely see the sky, and it’s a very heavy atmosphere.

There are so many face-swapping scares in the movie. How many of them were practical camera tricks vs. special effects?

A lot of it is in camera. The scene in the nightclub where he comes in and he’s on this dark, lethal, vengeful journey, I wanted to give the audience permission to enjoy his payback before it goes too far. There’s a lot of in-camera wipes. We did so much stuff old-school. He takes somebody out, then he goes past a pillar, then I knew that I’d use that pillar as a wipe, then I do the scene again with another actor and they’d come out of the pillar or Tom would come out of the pillar. It was really good fun.

Did you have a contortionist for the nightclub scene too?

My guiding thing is if I can do it practically, I will try and do it practically. So after that fall down the stairs, which is a stunt with two stunt people, then they’re all on the floor, we were like, “Well, should we try it with a contortionist?” for that sense of bodies out of shape. If you can do it in camera, why not, right?

That sequence also has a quick cameo from Aaron Paul, who plays Matt’s dad in one of his transformations. How did you get him to shoot that scene?

It was like, “Who can we get to play Matt’s dad?” And I really, really love Aaron Paul as an actor. I know it’s tiny, but I think he was living in Paris, and so somebody said, “Why don’t we reach out?” He’s such a nice man, and he came in and was just a really good sport and a really fine actor. It’s a tiny moment, and it’s a sort of really an Easter egg, isn’t it? But the idea that Matt’s not his father and sort of thing. It was a pleasure to meet him. He was like, “Yeah, cool DC movie. I’ll show my face for a moment.” It was very nice of him.

How did you decide on the final look for the Clayface monster?

I took everything as a reference and tried to choose, because there are so many versions in the comics. We did about 19 different iterations. You want to honor the comics, but at the same time, you want to make sure it can work as live-action because it’s obviously a different medium. The key thing for me was making sure that it captured the emotion, the man inside the monster. I was particularly obsessed with his left eye and the pain and the heartbreak within that and the scream, the quality of his voice. I first responded in Mike’s script to the idea of the tragedy and the journey of his character and where he ends up and going with him.

It was an awful lot of work and tiny tweaks. Where one fold of flesh goes makes such a difference. It’s sort of unquantifiable, but you just have to look at it and something about that feels good and real. It was a lot of work, but it was fun.

How did you pull off the suffocation scene where Matt kills his friend, Corey, by pulling him into his body?

The actual pulling into the body is practical with augmentation, but he is wearing a rig on his body with a big cavity in it so he could pull Josh [James], who plays Corey, into his chest. It’s like his face in the airplane. That is prosthetic makeup, not VFX. There’s a tactile quality that just reads when it’s on camera, that I think is very hard to replicate.

So the airplane scene, where he has to cut the strips of clay between his eyes with scissors, is mostly practical?

He had contact lenses, and then he had prosthetic makeup on. He actually had five pairs of scissors. We had sharp ones, blunt ones, rubber ones, one with a green screen tip, one without a tip. It was all on a gimbal, so the bathroom could move in real time and create the jolts. I was on the microphone talking everyone through the scene and jolts and Tom’s reactions. Tom figured out a way to — it sounds awful — where he could shove it in slightly above his eye, but the way it reads on camera, you can’t tell. He was quite in control and safe. For the close-ups, we had an eyeball, which was enormous, with a massive pair of scissors.

How many different facial prosthetics did you have for Tom to wear?

We had so many stages. I can’t say how many prosthetics, but we had like 65 stages at one point. That was all with bandages and this and that, but there was an awful lot because there were subtle differences between different melts and droops, and some that can have a pulley that you could tug. Obviously, some of these things you can augment with VFX because Tom can’t literally do that. But always having that base layer again gives you something that has a sort of heft to it.

I kept looking for a bat flying around or some kind of reference to Batman, but there isn’t anything overt. Did you ever plan to include more Easter eggs in the movie?

I actually think there are lots of Easter eggs that I probably don’t even know about because the graphics department was always throwing in posters and stuff. What I really responded to was the fact that it was a standalone story, and so for me to read that and then to try and get too cute or crowbar something in that wasn’t merited to the narrative felt gimmicky, I suppose. There was zero pressure to do it. I signed up to a certain story, which I believed in, and I just tried to tell that to the best of my abilities.

After the movie ends, do you have any plan for where Clayface goes next? Is he getting ready to fight Robert Pattinson’s Batman or another DC hero?

That’s a question for James Gunn. I liked the standalone nature of it. I liked how it felt like it introduced a character. But I wasn’t trying to introduce the character to go, “OK, what next?” I was trying to introduce the character as a full meal in itself.