You probably know today's guest blogger, Keegan Allen, best as sweet, sensitive Toby on ABC Family's "Pretty Little Liars." Which flick gives Keegan the heebie-jeebies? "The Exorcist"!

The scariest movie I have ever seen, and my favorite horror film is, “The Exorcist." It is a must-see horror/thriller classic. I watch it every couple of years. I have read interviews with the film's famous director, William Friedkin, and he said the award-winning film gets its real “scare” from the feeling that as you watch it, that “demonic possession” could really happen!! Bringing in the church and its teachings adds to the real fear that the devil could move in to your soul!! It scares me still.

When I was in high school, my friends and I would drive out into the country to abandon houses and structures…haha…to ghost hunt. We would scare each other sooo bad!! We would sometimes camp out by the abandoned buildings just to scare ourselves!! Such good times. The adrenaline of real fear is so cool!! So glad they asked me to write this blog, now I have a great reason to watch, “The Exorcist” again!!

Please check it out, but remember it's “R” rated so check with your parents first if you're too young. Have fun, be scared!!

Read all of our My Favorite Scary Movie guest blogs!

Have you watched "The Exorcist"? What's your favorite scary movie? Tell us in the comments and on Twitter!