Some spoilers follow.

Most of The Hole In the Ground (read our review) follows the A24 minimalist aesthetic. In the film, Sarah (Seana Kerslake) suspects her son Chris (James Quinn Markey) has been replaced by something else. He acts really creepy and there are a few violent scares, but it’s mostly buildup. And then Sarah enters the titular hole in the ground to try to save him, and that’s where you see the changelings in their true form.

Director Lee Cronin spoke with Bloody-Disgusting this week about the film’s creature design. His monster is practical, performed by someone with scary flexibility.

“In terms of practical elements, it’s actually a contortionist performer in prosthetic,” Cronin told us.

“It’s a European co-production. It’s Irish, Belgian and Finnish. Some of the casting came from Finland so there are some great circus performers in Finland actually so I lent on my Finnish producer and put the call out. We found this guy, Miro Lopperi, he was just so game for it. We only really had a day with him to get what we needed but he was all over it and he brought a lot of value to it as well.”

Okay, maybe it’s not 100% Lopperi, but it’s mostly him. “There’s not a lot of a creature in the movie, not a lot of monster, but what you do see, I would say 90-95% of it is real,” Cronin said.

“There’s very, very little CG. There’s a little bit of CG assistance in some parts and some comp work obviously.”

Star Seana Kerslake never got to work with Lopperi, however.

“For some of the shooting we did with Seana, we used a more temporary solution,” Cronin said. “We shot a lot of those monster elements separately but there was definitely something for you to interact with at the time.”

The mythology behind the creature is somewhat vague in the film. Sarah doesn’t know what she’s dealing with, so she can’t just microfiche it in the local library. Cronin knows a bit more than his lead character does, but the point wasn’t to establish a deep mythology.

“I wouldn’t say it goes crazy deep,” Cronin said. “I’ve got my own mythology that I built using existing lore.”

“I utilized that to spike in moments throughout the story. The myths that I lent on are maybe a little bit lighter and more airy than The Hole in the Ground actually is so as I said, I lent on some of that Irish stuff in terms of changeling mythology and some of those other darker corners. Really, because it’s such a singular POV in the film, Sarah’s journey, I didn’t want there to be a mythology that she could grasp onto. She’s falling headlong into this situation. I do think what’s interesting, what reflects James’s behavior when he’s altered in the film as such would be the want of those that live in this darker place to have the glamour of being human and to do all and anything possible to just fit in and be normal in a lot of ways. That’s why his reactions are actually instinctive to protect from the thread of Sarah maybe unmasking him.”

The Hole in the Ground is a DirecTV exclusive starting January 31 and opens in theaters March 1.