'Antlers' star Keri Russell and director Scott Cooper break down that horrifying ending

From the very beginning, Antlers signals that it's going to be an emotionally heavy ride even by the standards of modern horror. The story of two families reckoning with evils both human and inhuman in a small Oregon town, director Scott Cooper's film is a slow descent into darkness for adult and child characters alike, all building to an ending that lives up to all the heart-wrenching action that's come before.

According to star Keri Russell, who plays schoolteacher Julia Meadows in the film, and Cooper, the film's finale was often as challenging to shoot as it was to watch, as the cast and crew worked to find the right balance of emotion and creature-driven terror, with two young actors along for the ride.

**SPOILER WARNING: There are spoilers for the ending of Antlers ahead.**

Well before she's aware that it's happening, we as an audience know that Antlers is setting Julia on a collision course with a monster, a creature slowly transforming out of the man that was once Frank Weaver (Scott Haze). We eventually learn that the creature is a wendigo, a manifestation of human trauma and cruelty that infected Frank in an abandoned mine and now threatens to consume his entire family, including his sons Lucas (Jeremy T. Thomas) and Aiden (Sawyer Jones). Julia's concern for Lucas in particular, and her belief that the boy is in terrible danger, culminates in a showdown in the same mine where Frank's transformation began, as the wendigo emerges as a fully-formed creature, ripping off what's left of its human visage as it battles Julia.

"That was awesome to do all of that stuff because practically there was this creature in front of me," Russell tells SYFY WIRE. "It's not CGI. Because it's under [producer Guillermo del Toro's] movie monster magic, there was an actual creature there with people working it. It was amazing to do that because I wasn't having to imagine tackling something. It was there. What you see in the movie I actually got to work with. So, that was amazing."

Julia's head-on battle with the wendigo represented, for Cooper, a metaphorical struggle against the monstrous memory of her own father, who abused her as a child and drove her from her hometown for years, something composer Javier Navarrete's score references through subtle piano notes in the final battle. But defeating the wendigo and removing its burning heart is not the end for Julia, because Frank's transformation didn't just change him. The monster battle looms so large that we as an audience might forget, if only for a moment, that Frank has also infected his youngest son Aiden, leaving Julia with the terrible task of ending the little boy's suffering before he can fully change.

According to both Cooper and Russell, that moment marked one of the shoot's most challenging days, because it called for balancing the horror elements with taking great care to protect the emotions of the film's youngest cast member.

"You're in a very dark and dank space, there's a big monster, [Sawyer Jones is] 7 years old, his brain isn't formed, he's still just a baby," Cooper says. "He's trying to play very, very emotionally trying circumstances that would even try a veteran actor like Keri, and as a parent, you want these young boys to feel very comfortable to go to those places and to realize this is all just make believe. We're in a giant sandbox and we're having fun, but these are some tougher moments. That's one of the toughest moments that I've had to film in any of my five movies. And Keri and I had some very specific and distinct conversations when we got to that particular moment."

When it came time to shoot the moment when Julia has to confront the transformed Aiden as Lucas looks on, Russell and Del Toro both argued for some additional context to the scene. As Cooper recalled, it was important to his star that she turn to her young co-star and acknowledge what she was about to have to do to his little brother.

"[Russell said] 'He has to really understand what I doing or I'm not going to... because I don't feel comfortable as a mother, as Keri Russell, not as Julia Meadows. I want the brother to know that what I'm about to do is something that will irrevocably change his life. And it's very troubling for me as a mother, not as an actor, to have to play this moment,'" Cooper recalls.

But even that is not the end of the darkness in Antlers. With the confrontation in the mine concluded, and the wendigo seemingly defeated, Julia prepares to take on Lucas as an adoptive son alongside her brother, the local sheriff Paul (Jesse Plemons). But as the trio tries to move on from the carnage, Paul makes a final discovery: His wounds from the wendigo encounter have seemingly infected him, setting the stage for more monstrous transformations to come. For Cooper, the moment was less about trying to set up a continuation of the story, and more about making one final thematic point about the wendigo legend.

"I will say that in my research with the indigenous professor, Grace Dillon [who consulted on the film], she said that the wendigo lives within all of us," Cooper says. "It's a certain pain and misery that we can never escape from, regardless of your culture. And unfortunately, it's Paul's turn. We see that he, at the beginning of the film, is starting to meet with some opioid use. And we see it a little bit later. So he's dealing with his own grief and trauma of living with a monstrous father, as Julia has. So eventually it gets us all, but I think it's his turn at the moment. And I have been asked quite frequently about a sequel. Of course, I was never thinking in those terms, but only in thinking that, well, eventually it will come for you..."

Antlers is now in theaters.