In the fall of 1979, a group of unknown actors, a director desperate for a hit, and a special effects visionary got together in the woods of New Jersey to create the stuff of legend. Friday the 13th was supposed to be a simple exercise in good movie business, a film that would make money thanks to clever manipulation of the horror genre and some gory scares. Instead, it became a watershed moment in horror filmmaking, a landmark that has inspired countless imitators and nearly a dozen sequels.

Today, Friday the 13th is an essential slasher classic, but the road to success wasn’t exactly easy. To celebrate the film, and its often tumultuous production, here are 17 facts about the birth of the legend of Jason Voorhees.

1. THE ORIGINAL INSPIRATION WAS HALLOWEEN.

In 1978, producer and director Sean Cunningham was looking for a model on which to build a commercially successful film, and he found one in John Carpenter’s horror classic Halloween. The two films ultimately don’t share much other than very broad slasher tropes, but Cunningham says he “was very influenced by the structure of Carpenter’s film.”

2. THE FILM WAS BEING ADVERTISED BEFORE IT EVEN HAD FINANCING.

Hoping to drum up publicity for his project, Cunningham took out an ad in the July 4, 1979 edition of Variety, featuring the film’s now-iconic logo bursting through glass. At the time, the general structure of the film was in place, but Georgetown Productions had not yet fully agreed to finance it, and the advertised November 1979 release date was a pipe dream. Still, Cunningham did get a response from the ad. “Everybody wanted this film,” he later said.

3. THE SCREENWRITER HAD A DIFFERENT TITLE IN MIND.

Though Cunningham very quickly latched on to the idea of Friday the 13th as a title, well before the film got made, screenwriter Victor Miller originally came up with something else. In the spring of 1979, he was calling the film Long Night at Camp Blood.

4. MANY OF THE SPECIAL EFFECTS WERE “BAKED” IN THE CAMP’S KITCHEN.

Tom Savini is now a makeup effects legend thanks, in part, to his work on Friday the 13th. And in making the film, he and assistant Taso Stavrakis actually ended up using the camp to finalize the special makeup effects. According to Savini, many of the latex appliances ultimately used to create the film’s gruesome murders were baked in the pizza ovens at the camp where the movie was filmed.

5. THE CAMP USED FOR FILMING IS STILL OPERATIONAL.

Camp Crystal Lake is actually Camp No-Be-Bo-Sco, a fully operational camp that the cast and crew were granted access to after campers left for the summer in 1979. It is still in use today.

6. KEVIN BACON WAS NOT THE FILM’S BIGGEST STAR AT THE TIME OF SHOOTING.

Paramount Pictures

Though he’s without question the biggest name in the movie now, Kevin Bacon hadn’t done much prior to Friday the 13th, apart from things like a small role in Animal House. At the time, the film’s biggest name was Harry Crosby, son of then-recently-deceased legendary singer Bing Crosby, who played Bill.

7. SHELLEY WINTERS WAS THE FIRST CHOICE FOR MRS. VOORHEES.

For the now-iconic role of Mrs. Pamela Voorhees, Cunningham and company went in search of an actress with a recognizable name whose career was nevertheless on the decline, so she could be paid relatively little and the budget could stay low. Cunningham eventually made a list of actresses he was considering, and two-time Oscar winner Shelley Winters was his top choice. Winters wasn’t interested, and while fellow candidate and Oscar-winner Estelle Parsons actually negotiated to be in the film, she ultimately backed out. Cunningham also considered actresses Louise Lasser and Dorothy Malone right up until filming began, but ultimately the production wound up with Betsy Palmer in the role.

8. BETSY PALMER TOOK THE PART SO SHE COULD BUY A NEW CAR.

When Cunningham finally got around to offering Palmer the part of Mrs. Voorhees, she suddenly found herself in need of cash. After more than a year on Broadway, her car broke down as she drove back to her home in Connecticut. She might never have taken the movie if she hadn’t needed the money for a new car.

“I got home at five in the morning, and it was a situation where I desperately needed a new car,” Palmer said. “If I hadn’t needed a car, I don’t think I would’ve done Friday the 13th.”

9. SEVERAL CREW MEMBERS PLAYED THE KILLER BEFORE PALMER WAS CAST.

Even as filming got underway, Cunningham was still looking for an actress to play Mrs. Voorhees, so many of the early murder scenes were actually shot without Betsy Palmer, with members of the crew standing in for the hands of the murderer. For example, when Annie’s (Robbi Morgan) throat is cut early in the film, special effects assistant Taso Stavrakis is the one wielding the knife.

10. BETSY PALMER GAVE MRS. VOORHEES A DETAILED BACKSTORY.

When she was finally cast, Palmer dove deep into her character. As a Method actor, she wanted to know more about the character than the audience, and came up with a backstory that built on the killer’s hatred of sexual transgression. In her mind, Pamela had Jason out of wedlock with a high school boyfriend, and her parents ultimately disowned her for her sins because that “isn’t something that good girls do."

11. JASON WAS JUST A REGULAR KID IN THE FIRST DRAFT.

Paramount Pictures

In Victor Miller’s original script, the character of Jason Voorhees was, basically, just a kid who accidentally drowned in Crystal Lake. But financier Philip Scuderi wanted something more, and brought in screenwriter Ron Kurz for some rewrites. One of Kurz’s most important contributions to the film was to transform the tragic boy into the deformed child we see in the final movie.

12. DURING FILMING, THE CREW WAS ENTERTAINED BY LOU REED.

Because the camp was closed during filming, and situated in the deep New Jersey woods, the cast and crew didn’t see much outside interference, but it turned out they had a very famous neighbor: rock star Lou Reed, who owned a farm nearby.

“We got to watch Lou Reed play for free, right in front of us, while we were making the film,” soundman Richard Murphy said. “He came by the set and we hung around with each other and he was just a really great guy.”

13. ONE ACTOR WAS TEMPORARILY BLINDED BY FAKE BLOOD.

For the scene in which Bill (Harry Crosby) is killed by multiple arrows, one of which lands in his eye, Tom Savini used a fake blood formula that included a wetting agent called PhotoFlo, which was supposed to make the fake blood soak into clothing and look more realistic. Unfortunately, PhotoFlo is not an ingredient used for “safe blood,” meaning blood that’s going to be encountering the face of an actor. For the arrow-in-the-eye moment, a latex appliance was applied to Crosby’s face, along with the blood. As the scene was shot, the blood welled up into Crosby’s eyes, causing intense pain when the appliance was removed.

“So our unsafe blood had an opportunity to fill up Harry’s eyes under the appliance used to keep the arrow looking like it was in his eye and it surface-burned poor Harry,” Savini said. “Not a proud moment.”

Crosby had to be taken to the hospital for treatment, but was ultimately fine.

14. KEVIN BACON’S ICONIC DEATH TOOK HOURS TO FILM (AND ALMOST DIDN’T WORK).

Perhaps the most iconic death in the film occurs when Jack (Kevin Bacon) is killed with an arrow shoved through his throat from underneath the bed he’s lying on. It’s a brilliant special effects moment, and was also the most complex death scene in the film. To make it work, Bacon had to crouch under the bed and insert his head through a hole in the mattress. Then, a latex neck and chest appliance were attached to give the appearance that he was actually lying down. Getting the setup right took hours, and Bacon had to stay in that uncomfortable position the entire time. For the bloody final moment, Savini—also under the bed—would plunge the arrow up and through the fake neck, while his assistant—also under the bed—operated a pump that would make the fake blood flow up through the appliance. To further complicate things, the crew needed someone to stand in for the killer’s hand as it held Bacon’s head down, and they settled on still photographer Richard Feury.

So, after hours of setup and latex building and planning, it was finally time to shoot the scene, and when the moment of truth came, the hose for the blood pump disconnected. Knowing that he basically only had one take (otherwise they’d have to build a new latex appliance and set everything up again), Stavrakis grabbed the hose and blew into it until blood flowed out, saving the scene.

“I had to think quick, so I just grabbed the hose and blew like crazy which, thankfully, caused a serendipitous arterial blood spray,” Stavrakis said. “The blood didn’t taste that bad either.”

15. THE FINAL SCARE WAS SUPPOSEDLY NOT IN THE ORIGINAL SCRIPT.

The story of who invented the final scare in the film, in which a deformed Jason bursts out of the lake and grabs Alice (Adrienne King) from her canoe, is disputed. Victor Miller, Tom Savini, and uncredited screenwriter Ron Kurz all claim credit for it, Kurz because he claims to be the one who made Jason into a “creature,” and Savini because he claims the moment was inspired by a similar final scare in Carrie. Whatever the case, it left a lasting impression.

16. THE MAIN THEME MUSIC CAME FROM A LINE OF DIALOGUE.

When composing the score for the film, composer Harry Manfredini was looking for a distinctive sound to identify any point when the killer appeared in a scene. When he first saw a print of the film, he heard Mrs. Voorhees, imitating Jason, saying “Kill her, Mommy!” and decided that was the key. So, he took two syllables from that line of dialogue, spoke them himself, and made the iconic sound.

“So I got the idea of taking the 'ki' from 'kill' and the 'ma' from 'mommy,’ but spoke them very harshly, distinctly, and rhythmically into a microphone and run them through this '70s echo thing. It came up as you hear it today! So every time there was the perspective of the stalker, I put that into the score,” Manfredini said.

17. THE SCREENWRITER HATES THE SEQUELS.

Paramount Pictures

One of the key twists of the original film, particularly in light of its many sequels (counting a crossover with A Nightmare on Elm Street and a reboot, there are 11 now), is that Jason is not actually the central figure. He provides a haunting mythology, but the real villain is his mother. For screenwriter Victor Miller, this was very important, and he framed Pamela Voorhees as the mother he never had, a woman who tirelessly professed love in her own crazy way. When the film became a hit, and the inevitable sequel featured Jason as the new killer, Miller was disappointed.

“To be honest, I have not seen any of the sequels, but I have a major problem with all of them because they made Jason the villain,” Miller said. “I still believe that the best part of my screenplay was the fact that a mother figure was the serial killer—working from a horribly twisted desire to avenge the senseless death of her son, Jason. Jason was dead from the very beginning. He was a victim, not a villain. But I took motherhood and turned it on its head and I think that was great fun. Mrs. Voorhees was the mother I'd always wanted—a mother who would have killed for her kids.”

Additional Sources: On Location In Blairstown: The Making of Friday the 13th by David Grove (2013)