When Stephen King first introduced audiences to Pennywise in his novel It, and later the TV miniseries with Tim Curry, he was drawing from a long history describing the dark side of the clown. But the type of clown most people were familiar with is of course the good, happy clown. So these scary clowns subvert that idea, and that’s one reason they’re so interesting and compelling.

King of course didn’t invent the idea of the scary clown, though he certainly helped popularize it. (Evil clown films date back to the silent era, with 1924’s He Who Gets Slapped, starring Lon Chaney Sr.) Clowns have always been with us and the character, historically and culturally, has always been an ambiguous person — neither good nor bad, but sometimes either or both. The clown is a trickster figure, as is the Devil, so there has always been an element of the unexpected, the scary or threatening in the clown.

So it’s misleading to ask when clowns turned bad, for they were never really good. The evil clown character may have flourished and found new fame over the past few decades, but there is nothing new about it. Mythologist Joseph Campbell, in his classic The Hero With a Thousand Faces, notes that in mythology the clown and evil are inextricably linked: “Universal too is the casting of the antagonist, the representative of evil, in the role of the clown. Devils–both the lusty thickheads and the sharp, clever deceivers–are always clowns….”

Of course on a subconscious level, any unknown person in disguise who stands near us or interacts with us might freak us out. Masks hide almost all of the non-verbal communication we ordinarily get from others. If a clown’s grease-painted smile can vanish with the wipe of a dirty rag, then for all we know the man behind the mask could be very different. What are they thinking? What are they going to do?

Clowns may be scary to many people, but they are not inherently threatening, the way a coiled rattlesnake or a knife-wielding mugger is. The fear of clowns stems from a latent, potential harm, a suspicion that the seemingly silly and harmless pratfalling fool before us may in fact not be so silly, so foolish or so harmless. Most of us (the adults, anyway) understand that the clown is an act — a fake and fantastical persona adopted for a short time as part of a social event. It can be cute and funny at the time, though we may not want to be around when he decides to stop acting.

Thus you can never really trust a clown because you don’t know what they’re going to do; surprises are part of the act. It’s also unclear what’s a performance and what’s not. In my book, Bad Clowns, I have a chapter on “dip clowns,” or dunk tank clowns, who insult passersby at fairs: Ridiculing people’s weight or bad toupee is all part of the fun — but we don’t know what the clown really thinks. Is the clown just pretending to be vile and nasty, or is he really like that?

I also discuss coulrophobia, the fear of clowns, although it’s not as widespread as you might think. Hating clowns is sort of a hip, fashionable thing to do, but very few people have a genuine, clinical phobia of clowns. People don’t share stories of creepy clowns because they are legitimately afraid of them, for the same reason that an arachnophobe wouldn’t share close-up photos of spiders on social media. People share the stories for the same reason they share anything else–it’s creepy/funny, novel and sensational.

We love evil clowns because they embody fascinating contradictions of humor and horror, so they’re not going away any time soon!

It, directed by Andy Muschietti and written by Chase Palmer, opens this weekend.

The Critical Angle is a recurring feature that uses critical thinking and skepticism to analyze pop culture phenomena. Skepticism is an approach to evaluating claims that emphasizes evidence and applies the tools of science. While it’s often utilized to investigate claims of the paranormal, skepticism can be used when considering just about anything.