A Monster Calls stars Felicity Jones as Conor's mother; Sigourney Weaver as his brusque, icy grandmother; and Liam Neeson as the voice of the monster. It's based on a children's book by Patrick Ness (author of the stunning Chaos Walking YA series), who also wrote the screenplay. Bayona and I talked about the process of refining that screenplay with Ness, but also about why he built a huge live-action version of his CGI monster, and why he isn't worried about his terrifying creature looking kind of like Groot from Guardians of the Galaxy.

On the surface, there isn't a lot of common ground between J.A. Bayona's 2007 creepy ghost story debut The Orphanage, his tsunami disaster tale The Impossible, and his new film A Monster Calls, a tremendously effective tear-jerker about a young British boy named Conor coping with his mother's illness by sneaking off to confront a roaring, blazing tree-monster that insists on telling him fables. But all three films are about mothers and sons, about loss and grieving and coping, and about the strength of family bonds even in catastrophic situations. When I sat down with J.A. Bayona at the Toronto International Film Festival a day after the world premiere of his film, he teased out something else that all three of his features have in common, which speaks more to Bayona's own mythical storytelling style than anything else.

This is your third film in a row about loss in the relationship between mothers and sons. Why is that such rich territory for you? You just follow the material that creates strong stories. This was an accidental trilogy, but I thought A Monster Calls was an interesting way of closing it. The three films talk about these things from a different point of view, and that's interesting. The Orphanage talked about growing up from the point of view of pathology. This woman can't cope with maturity, and has a Peter Pan complex. The Impossible is about growing up in a bigger sense, how it is to realize as a Westerner [that you have] privilege, compared to other people. And this film is more about finding the truth, and being able to express it. That connects to the monster's storytelling, and to what we do as storytellers. I researched [the tradition of] storytelling and found it fascinating, like finding the meaning of a dream. "Wow, so this is why this material connects with me." "everyone watching is Conor, everyone is a monster, everyone is a mother." A Monster Calls feels more like a Guillermo del Toro project than anything you've done before, including The Orphanage, which del Toro produced. You met him when you were 17, and he said he would help you as a filmmaker. What do you think it was that made such an impression on him? I think it was the way I look. He said I was like a kid with sideburns, asking questions all the time. And then he started to see my short films and music videos, and he wanted to be involved in my career. He made The Orphanage possible. And we keep in touch. Is he an ongoing influence? Again, this feels like one of his films, specifically in the way it addresses how we need storytelling to express our emotions and define ourselves. The idea of storytelling is to transcend, to reveal a truth that feels more real than reality itself. From the moment you start to create a story, that's the goal. The particularity of this film is that it talks about that directly, but all films are about that. The other day I was reading a very interesting book on heroes. This writer said that literature about historical facts is about one person, but literature in general is about human beings. So this is the goal of every story, to make the story appealing and universal in a way everyone can relate to, so by the end of the film, everyone watching is Conor, everyone is a monster, everyone is a mother. I think this is why it's so important to keep a mystery. The Orphanage, The Impossible, and A Monster Calls, they each end with a question: what's the meaning of that last shot? What's the meaning of that scene? There's no specific meaning. Everyone has to put their own meaning into the story. And that's what makes the story eternal. Because it will be different every time you see it. Because there's a question, and it hasn't been answered.

Courtesy of TIFF

You've said in the past that it's possible to read The Orphanage as if none of the ghosts are real; that it's just someone in shock and denial, hallucinating and making up a comforting story. You could easily say the same thing about Conor here, that the monster is all in his head. Are you at all interested in the question, "Is this real?" I think it's the mystery we're talking about. I think that ambiguity is what keeps the movie alive. It's something organic, something that keeps working on your mind once you leave the movie theater. When your Orphanage and Impossible screenwriter Sergio G. Sánchez first brought Patrick Ness' book to you, what did he want you to see in it? What excited him so much about it? Sergio had a strong connection to it for personal reasons. He was obsessed with the book. But I didn't read it immediately. Then my agent sent me the script version. And I thought, "Sergio and my agent both know me very well, so there must be something here." So I read the book, and then read the script, and then met Patrick Ness. And I realized, because I was so interested in storytelling, and in the way it asks what's behind the stories that connect us, this story was perfect. It was dealing with themes that were already near the movie's. It was so relevant to me. You worked with Patrick personally on developing the script from his original draft. What did you want from him, in terms of making it a better film? I was trying to find the ultimate meaning of every single moment in the story. It's a multi-layered story full of psychological complexities, philosophical implications. We could spend hours talking about it, trying to make it even better. One idea we worked on, which isn't in the book, is the legacy of people in our lives, how a legacy makes someone alive even if they aren't here anymore. That was my way of finding light at the end of the story, through the idea of legacy. How did you visually develop the animated story-within-a-story sequences? What were your inspirations there? I have lots of friends who are illustrators, and we talk a lot about how what you don't see is more important than what you can see in a painting. In that sense, I didn't want to see the faces of the characters in the animated stories. For me, they're more ideas than characters, so I thought, "I don't want to see actors playing them." I realized the best way to do that was with drawings. So then it made perfect sense that Conor himself drew the characters. That created an immediate connection to me, because I was obsessed with drawing when I was a kid. And then I started to feel the whole story in an even more personal way. So how did you work with the animation house to develop that bright, flat, vivid storybook look? There is a company in Barcelona called Headless, and I was a huge fan. I love their style. I had been trying to work with them for years. A Monster Calls was the perfect project to work on with them. They followed my idea that I wanted the animations to be more and more real as the story goes on, as a way of telling the audience that fantasy was becoming more real to Conor than reality itself. So we started with 2D animation, then worked into 3D animation. There is a moment where the characters get into the animation world, and ultimately, the last two tales take place in Conor's reality. So the style helped with the progression of the stories in the film.

What did you want to achieve with the look of Conor's monster? We did, like, 200 designs. We tried maybe 200 different drawings of the monster, and there was a moment where I finally realized you cannot do anything that hasn't been done before. Everything you can create that looks like a tree will remind you of the Ents from Lord Of The Rings. Everything that looks like a man will remind you of other creatures. The Green Man is such an important figure in mythology that you will find hundreds of designs for that. So after doing 200 designs, I realized that there was something powerful in Jim Kay's drawings, because his design was so simple. It's just this dark figure of a man. Ultimately, the monster is the man Conor is going to become. It's his own conscience telling him, "You need to break things, and then you will find your place in the world." So I thought, "The more simple we go, the more space we leave for imagination in the audience. So instead of giving it eight legs and three eyes, let's keep it simple." When you see the monster in the dark, you almost can't see him, and that is great for the audience, because they can project their own idea of the monster. "Everything you can create that looks like a tree will remind you of the ents from 'Lord Of The Rings.'" One thing that makes it very distinct is the fire inside the monster, the way it blazes along its seams. Well it's one of the few things that the monster actually does. I didn't want to spoil the audience's imagination, so I wanted to keep the monster as simple as possible. But the fire came from the idea of rage. The mythology of the Green Man is very grounded in the earth, the land. And I thought, "One of the things that connects trees with the land is fire." And I thought about fire when the tree was giving birth to the monster. So he's red like a baby when he's born. And that fire is the fire of rage, the rage inside of Conor. You built physical versions of the monster, a giant full-sized face and hands and feet, and it sounds like that was a tremendous effort. Why was it important to you to have that practical effect as well as CGI? With the ending of the film, we had to be very careful in telling such an important moment. I won't spoil the ending, but in the last scene where you can see the kid and the mother and the monster, I was very worried about putting a lot of visual effects into that scene. I didn't want the effects to be distracting. So we built the head of the monster, the arms, so that what we had on the set was real, and we could work from there. It was great, the first time that I saw that scene completed, because I realized the special effects weren't stealing the moment. It was a moment for the actors, but at the same time, we had these amazing visual effects. I felt good the first time I saw it. That tells you how much I wanted the visual effects to be grounded at the time. This is why the monster doesn't do anything that looks very spectacular.