Over 90 minutes, Katie Featherston gets closer to the devil than most people do during a lifetime.

In Oren Peli's Paranormal Activity, Katie and her boyfriend Micah square off against a demon that wants more than just to disrupt their sleep. During the course of the movie, the evil within their household gradually breaks Katie down in a tangibly terrifying fashion. This is easily the scariest film about possession since The Exorcist, and it all feels so real due to Katie's performance. Paranormal Activity explores a variety of nightmares from fear of the dark and the unknown to the terrifying concept of losing all control.

So Katie got to spend some time with Satan and she sat down with ARTISTdirect.com editor and Dolor author Rick Florino to talk all about it in this exclusive interview.

She discusses how "real" Paranormal Activity got at points, getting into her character's head and the movie's kinship with Marilyn Manson. Get Paranormal Activity on DVD now.

Would you say that the most frightening element of the film is the loss of control—even more so than the possession?

Katie: Yeah, I think the idea of losing yourself was definitely a big part of it. As well as possession, the movie is about not being able to know who you are anymore. That's a pretty frightening thing. Coupling that with the kind of movie it is—it's really about what you don't see. It's a quiet scare that gets under you scare. For me, those elements combined felt very effective and made me excited to delve into this as opposed to just having a lot of jump scares to react to.

That fear translates beyond the film's landscape. A lot of people growing up experience that while just trying to figure out who they are.

Katie: Absolutely! The movie's relatable on many levels. There's that level. On a plainer level, everyone has been in or knows someone in a relationship and everyone goes home to his or her house or apartment and turns off the lights. Everybody has to go to sleep at night. There's something a little deeper that anyone can relate to which makes Paranormal Activity all the more scary.

Did you get to learn about all of that occult lore surrounding the film?

Katie: Oren [Peli, director] was really great about that, and he did research for a long time. He shared a lot of that with us; giving us movies to watch and things to read. It was very important to all of us. If we were going to make a movie that looked realistic and had that feeling of real footage, everything that you see in it had to be based in reality. We didn't want to have this realistic-looking movie and have things happen in it that have never been reported or can never happen. All of the different scares are things that have been recorded to have happened to people at different times. A lot of Oren's research fed into Micah's character that's doing research in the film and trying to figure it out. He's joining those two things in the film.

Was there any instance that you learned about that particularly freaked you out?

Katie: I got to learn about exorcisms and what those entail. There was one exorcism where the girl actually died because they basically starved her death. They were trying to rid her of the demon, and there were a lot of stories like that one, which were disturbing and creepy. Those stories really got us into that mindset for the movie though.

In some ways, it's like the movie possesses the viewer, creeping in slowly and taking up residence in the psyche.

Katie: From the time you walk into the theater to the time that you leave, we wanted the movie to seem real and be accessible. If you could get sucked into it and it felt like you were just watching real people that could be you, that was our goal. If that happened or worked on any level, that's pretty exciting.

Paranormal Activity is more like a book than a film in some ways because the audience really gets inside Katie and Micah's heads. You also show every emotion imaginable too.

Katie: To Oren's credit, he was very focused on making sure that our relationship was just as important in the movie as the scares were. If you care about the characters then you're going to care what happens to them and it's going to be that much scarier. If you don't really care, it's not going to be as effective. It was important to all of us that Micah and I are easy to relate to in the film as the movie progresses and the relationship breaks down. That was an important part of the film. The movie is really about what you don't see. Your own imagination is a lot scarier than anything you could see on the TV or movie screen. It's the kind of fear that gets under your skin and sticks with you. It's a time to re-awaken all of those fears you had as a kid—what's under the bed, what's in the dark? It opens that door back up in a more adult situation.

Did you listen to any music to get into Katie's character?

Katie: That's an interesting question! When I was doing theater back in college, I always had music that went with each character. Since then, acting's been about what's happening in the moment. It's less about listening to music or doing those sorts of things in preparation. Preparation's important, but it's really about knowing where you are and what's happening and having a point-of-view on what's happening. It's also listening to your partner—who in this case was Micah. For me, I knew I was in love with him and this was what was happening in our lives now. I had to take that information in love in the moment. It was much more about being in the moment because everything was so improv'ed since there was no script. We were creating in the moment, so it was very much about being on your toes.

If Paranormal Activity were an album what would it be?

Katie: [Laughs] I think it would be some sort of classical album sort of like Bach meets Metallica. No, it would be Bach meets Marilyn Manson [Laughs]. That's my thought!

—Rick Florino