They’re the movies that keep you up at night double checking inside the closet, under the bed, right over your shoulder. They’re the movies that make you scream, and capture your imagination. They’re the most terrifying movies ever made. But why? What do these movies do to your brain? What primal emotions do they tap into? What is about them that gives you… one good scare?

In this series, we’re diving into three of the scariest films ever made. We’re looking at them in terms of their overall scare quotient and exploring their legacy within the genre and the culture at large to determine why they succeeded in such massive and scream-inducing fashion. For our first episode, we’re tackling William Friedkin‘s 1973 blockbuster (before such a term existed) The Exorcist, which saw a young girl get possessed by a demon, a single mother attempt to help her in any way possible, and a faithless priest try to grapple with pure, unadulterated evil.

To help me get to the bottom of this, we’re joined by several experts in the field of scary things: Margee Kerr, a sociologist who studies fear and the author of Scream: Chilling Adventures in the Science of Fear; Ryan Turek, a longtime horror journalist and current director of development at Blumhouse Productions; Clarke Wolfe, the hose of Collider Nightmares and a friend and correspondent of this parish; Jill Killington, a horror author and director; and Daniel Montgomery, the artistic director of Creep LA, Los Angeles’ preeminent interactive horror experience. Everybody came to the movie in different ways and we’re all scared of it for different reasons, but we can all agree on one thing: This movie is frightening as hell.

Let us know what you think of One Good Scare in the comments below, and get ready for the next two episodes before All Hallow’s We’en and Nerdoween!

Kyle Anderson is the Associate Editor for Nerdist. You can find his film and TV reviews here. Follow him on Twitter!