In the new found-footage horror movie, Creep, Mark Duplass plays a man dying of cancer, and Patrick Brice is a videographer he hires to film his ruminations for his unborn child. Who else is in this film, which was produced by the Duplass brothers and scare-meister Jason Blum? No one, really. Indeed, for its first half, Creep is more interested in tracking the relationship that develops between the two protagonists than in delivering chills. And then? Well, that, folks, would be telling.

Duplass, Blum, and Brice—who also directed and, with Duplass, wrote the film—spoke to EW about Creep, which debuts on iTunes June 23 and will be available on Netflix from July 14. You can also see the film’s exclusive trailer above.

ENTERTAINMENT WEEKLY: Mark, are you a fan of horror movies? You’ve actually appeared in a few now, as well as being an executive producer on Bad Milo, the best butt-demon movie of all-time.

Mark Duplass: Thank you very much! I grew up watching horror movies, going to the mall as a little mall-rat skater-punk. But as a filmmaker, I’ve kind of stayed away from it. If you look at the, quote-unquote, “horror” projects that I have approached, most of them are based on inter-personal dynamics. Creep is kind of like a foreign arthouse film about feelings that happens to just take a darker turn.

What was the origin of the project?

MD: The idea started with me and Patrick sitting a lot in my living room. We got to know each other because his wife was the nanny to our children at the time. He had just graduated from CalArts and we became firm friends. He was talking about what his first movie could be. We are obsessed with odd human behavior and strange human beings. We’re big people-watchers, and we started talking about how much we loved My Dinner with Andre, and strange human dynamics, and then we started talking about making films which were a two-hander together. We were led to this concept of a Craigslist adventure gone awry.

Rather than develop it traditionally, and try to take it out to a studio or something, we decided to set aside a week and go up to this cabin and improvise this story out of a five-page outline that we had created. And then we made that thing, which was kind of a hot mess [laughs] but had some promise. I had been friends with Jason Blum from doing some other projects together. We came together and turned it into what eventually became Creep.

Patrick, were you unnerved by the idea of starring in your directorial debut?

Patrick Brice: It’s funny, part of the reason why we wanted to do this was, we wanted to make a project that was really contained. I’d acted years ago, in community theater, but I’d never done it in front of the camera. So I learned a lot doing it that way. It’s hard to be objective when you’re having to watch yourself but having Mark there and this immediate way of making a movie allowed us to make quick adjustments when we had to. Or if we had an idea, [we could] go out and film it quickly, and then watch it, and see if it worked or not.

Jason, what was the condition of the project when you signed on?

Jason Blum: It was a rough cut, which I loved, and thought was fantastic, so I threw my hat in the ring.

MD: You called me, and you were like, “All found-footage movies come to me, and they all suck, and this one doesn’t, and I want to help.”

Jason, as one of the folks responsible for bringing us the Paranormal Activity franchise, how many found-footage movies do land on your proverbial doormat?

JB: About one a week—probably more. They’re easy to make but very hard to make well.

Is it true that you remodeled a lot of the film after showing it to an audience?

MD: We would kind of test [the different versions] informally for our friends. We did the process which you normally do with your screenplay—show it to your friends—but because the movie was fast, and loose, and easy to shoot, the traditional development process actually happened with the shooting, as opposed to the writing. So we would shoot some stuff, we’d put it together, we’d show people. We shot over the course of 18 months, continually evolving it. And everybody who kept coming to the movie kept saying, “Make this thing darker.” That’s what everybody responded to, which was great.

When Jason and Patrick and I really started honing in on this thing we had a crossroads moment where we were like, “There is a version of this that could be a wide release movie but we would have to rub some of the edges off of it.” And we all decided, “Let’s just make it super weird and make it the crazy little monster that it is.”

I don’t think I’m spoiling anything to say that there is a fantastic wolf, or werewolf, mask in the film. Did you have that made? Or is that something I can buy in a store?

MD: Depending on the success of the film, you may have a chance to be wearing this thing for Halloween. Let’s just see how many clicks we can get on Netflix. That will determine a lot of it.

There have been rumors of a sequel…

MD: It’s definitely in the discussions. When you see the movie, and you see what this movie is about—which is, Why do we inherently trust people that we shouldn’t trust? Why is it that we put an ad in the paper and let a stranger walk into our home without knowing anything about them? That story is so exciting and so interesting. For fear of being rude, or offending people, we don’t protect ourselves. And that feels big to us. We definitely feel his is not the end for the stories of Creep.