Stephen King’s 1986 horror novel IT has undergone three vastly different adaptations while continuing to focus on the fear of its terrifying clown, Pennywise, who was inspired by true crime and societal fears. The clown became a symbol of childhood horrors come to life when he published the nearly one-thousand-page story. While it contains various themes of the paranormal, supernatural, and even science-fiction, the real-life inspiration that influenced King’s creation of Pennywise has remained the most horrific.

The novel was initially adapted into a made-for-television miniseries by Tommy Lee Wallace of Halloween III: Season Of The Witch fame. In 2017 and 2019, Andy Muschietti took on the task of adapting the novel once more for theatrical release. Both have found success among King fans, whether as a cult following in the case of Wallace’s miniseries or with critical acclaim like Muschietti’s. Staying true to the source material, both films follow the “Losers Club” as adults and children as they battle the evil clown known as Pennywise who is murdering children in the town of Derry, Maine.

Related: What Does Pennywise Really Look Like In IT?

Pennywise and his abuse of children is central to the plot line in every adaptation and in the book itself. While King was writing the lengthy novel, the influences of his surroundings and the headlines that were plastered all over news stations deeply impacted the creature that would become the heart of his novel. A shapeshifting clown from another dimension is scary enough, but the real-life influences that created him are even more disturbing and add an unnerving depth to the familiar horror icon Pennywise.

The John Wayne Gacy Murders

John Wayne Gacy was a notorious serial killer and sex offender who often dressed as a clown. He regularly performed at children’s hospitals in his clown attire under the name “Pogo the Clown” or “Patches the Clown.” On December 21, 1978, Gacy was arrested and convicted of 33 murders. He was sentenced to death on March 13, 1980, and executed by lethal injection on May 10, 1994. The IT character Pennywise may have been based on the serial killer.

While there is some debate on whether Gacy truly influenced the creation of Pennywise, the two are eerily similar, as both dress as clowns and target children. When Gacy was convicted of his murders in 1980, King must have begun writing IT. Whether it was a conscious influence or not remains unknown, but real-life horror often bleeds into fiction, especially when the reality is much more gruesome. Undoubtedly, the Gacy murders caused an immense amount of fear in the hearts of Americans, and once Pennywise was introduced, he further perpetuated the necessity to fear the people behind the white paint and red smiles.

The 1980s “Stranger Danger” Panic

IT - Pennywise and Stephen King

Another influence behind the IT novel was the "stranger danger" panic of the '80s. During the 1980s, a new wave of public fear permeated society. As the epidemic of child murders and kidnappings rose beyond belief, the “stranger danger” panic formed. Former president Ronald Reagan started the campaign for increased criminal penalties for anyone who attempted to or did harm children. During the Reagan administration, family values and safety were at the epicenter of his political platform. With the threat of Gacy and other child murderers, the stranger danger panic grew in severity.

Related: Did Pennywise Die In IT: Chapter 2? It's Complicated

When clowns don their face paint, rainbow suits, and wigs, they are nearly unrecognizable. Because of this fact, all real clowns become immediate strangers. With so many children's birthday parties including performances from these actors, the fear of a murderous stranger such as Gacy was an all too real threat to American society. Various moments in King’s novel allude to the stranger danger panic as a partial influence on the book, as the kids who interact with Pennywise often view him as nothing but an innocent party clown.

What Other Characters Inspired Stephen King's Pennywise

While Gacy provided the foundation for the horrors Pennywise would cause, Ronald McDonald was the model for his appearance. In various interviews, Stephen King has referred to Ronald McDonald as a trustworthy character that children know and love, making him someone they can trust. By modeling an untrustworthy horror creature after a beloved children’s icon, it created an unsettling divide of who or what can be a source of comfort or terror for children. This does not mean Ronald McDonald was the main source of inspiration for the novel, but his iconic look inspired Pennywise’s appearance.

Where Will Pennywise Appear Next?

It-1990-Pennywise

It was first announced in March of 2022 that a prequel series to Muschietti's IT would be rolling out on HBO Max called Welcome to Derry. The upcoming TV show recently opened up the writer's room, and the series is going to be set during the 1960s. Writer Jason Fuchs (Wonder Woman) is confirmed to be working on the show along with Shelly Meals (Shadow and Bone). While it's briefly explored in both IT and IT 2 (especially the latter), Pennywise has been a central figure in Derry's history as a small Maine town. Pennywise is evil incarnate and arrived on Earth sometime after the dinosaurs died out but before the ice age, terrorizing the area ever since.

In the book, the monster has been responsible for Derry's horrific events, such as the 1906 Kitchener Ironworks explosion (killing 108 people), the murder of the Bradley Gang, and an incident in 1904 in which lumberjacks slaughtered a number of men at a bar. Welcome to Derry will further explore the evil clown's influence on the town, and people will get to see Pennywise doing what it does best. Ultimately, Stephen King’s inspiration for Pennywise was derived from an array of sources ranging from real-life murders to far less sinister clowns. At the end of the day, his main reason for making the central creature of IT a clown was his own fear of them. Welcome to Derry should provide even deeper insight into Pennywise's real-life influences and horrific fictional qualities.

Next: The Mythology Of IT Explained: Origin, Deadlights & Eater Of Worlds