1984’s A Nightmare on Elm Street ushered in a new kind of serial killer: A motormouth who cracked dad jokes and reveled in puns. Unlike his more silent brethren in Halloween and Friday the 13th, Freddy Krueger exhibited a ghoulish glee in his murderous work that instantly made him the next big thing in horror.

At the time of its release, writer-director Wes Craven had already solidified himself as one of horror’s preeminent directors, with movies like The Last House on the Left (1972), The Hills Have Eyes (1977) and The Hills Have Eyes II (1984) and Swamp Thing (1982) under his belt. But Nightmare on Elm Street elevated him to a new level as his first franchise. It also cemented journeyman actor Robert Englund, who played Freddy, as a lifetime horror icon and introduced the world to Heather Langenkamp as Nancy Thompson, who in many ways deserves more Final Girl credit than she seems to get.

The original 1984 A Nightmare on Elm Street is now back in theaters for a limited time. To celebrate it, and the brilliance of the late Wes Craven, here are some fascinating facts I bet you may not have known.

1. It used a lot of blood.

Seriously, a lot. Over 500 gallons of fake blood were used during the shoot, which took 32 days.

2. But the famous blood geyser sequence didn’t use fake blood at all.

Instead, they used red-dyed water as traditional fake blood just didn’t look right in a geyser. To achieve the effect, the crew built a rotating set which they then inverted but attached the camera to appear as though the room was right-side up, while Craven and the cameraman sat outside the set and looked in through a window. The red water was then poured into the room from above but appeared to geyser up from the bed. During filming, the room accidentally spun the wrong way, sending the red water pouring out of the window and door, soaking Craven and Langenkamp and causing the electrical equipment to short out and shocking one of the crew members.

3. It took three hours for Robert Englund to get made up as Freddy Krueger.

Nightmare makeup artist David B. Miller based Freddy’s look on photographs of severe burn victims he saw at the UCLA Medical Center.

4. But it would have taken far longer had Wes Craven had his way.

Wes Craven’s initial concept for Freddy Krueger’s look was far more gruesome, including his teeth showing through a decomposing jaw, pus oozing out of sores, and part of his skull showing. However, Miller explained it was impossible to make up a human in that way to look realistic and an animatronic puppet would never blend in, so the idea was ultimately abandoned.

5. Freddy’s origin story was changed, too.

Originally, Freddy’s backstory in the script was that he was a child molester. However, at the time of production there was a rash of highly-publicized child molestation cases in California and Craven was worried it would appear as though he was trying to exploit that. So the decision was made to turn Freddy into a child killer, instead.

6. Wes Craven got the idea for the story in a series of articles he read in the LA Times.

Craven read a series of articles in the LA Times in the 70s that covered the bizarre case of hundreds of male refugees from Laos, Cambodia, and Vietnam suffering from a sleep disorder plagued by nightmares. Many of these men died inexplicably in their sleep, prompting medical experts at the time to dub it “Asian Death Syndrome.” It was later revealed to be related to a heart condition where the heart misfires during sleep, but the idea of something killing people in their dreams stuck with Craven.

7. Inspiration for Freddy also came from his childhood.

Craven got Freddy’s name from a schoolmate of his, Fred Krueger, who bullied Craven for years when they were children. (He’d previously named the villain in his 1972 movie The Last House on the Left Krug.) Freddy’s disheveled look, with the dirty clothes and hat and sweater full of holes, was inspired by a moment from his childhood in which an old homeless was walking along the sidepath near Craven’s house and stopped to stare into the window at Craven, who hid. When the young Craven looked out the window a few seconds later, the man was still there and made a scary face at him before walking away. Craven never forgot the image or the way the man seemed so delighted by his fear.

8. The knives used in Freddy’s iconic glove were tomato knives, not steak knives as people believe.

The exact kind of knife used in the razor glove is a Case XX P210 tomato knife. They were so sharp that Robert Englund actually cut himself the first time he tried on the glove, which was Freddy’s signature prop as Craven needed a unique weapon for Freddy that was still relatively cheap to make and easy to transport. At the time, Craven was doing research for the movie and reading about primal fears across all cultures; being attacked by animal claws is one of them. Later, Craven saw his cat unsheath its claws and the two ideas melded in Craven’s mind, forming the bolt of inspiration for Freddy’s iconic glove.

9. Simple tricks were used to create the two most iconic effects of the gloves.

The knife glove is known for two specific things in the movie: the teeth-on-edge screeching sound it makes when Freddy’s claws slide over a surface and the way it sparks whenever he touches metal. The sound effect was created by scraping a steak knife on the underside of a metal chair. The sparks were created by hooking up the glove to a car battery.

10. Freddy’s sweater was originally red and yellow.

Craven originally based Freddy on the color scheme of DC comics hero Plastic Man. Like Plastic Man, Freddy could change his shape and the idea was that Freddy would be red and yellow no matter what he turned into. However, after reading an article in Scientific American that said red and green are the two colors that clash most in the human retina, Craven changed Freddy’s color scheme to that.

11. It quite literally saved New Line Cinema.

At the time of production, New Line was on the verge of bankruptcy. The studio was so broke that it almost folded in the middle of the shoot. Smart Egg Productions, which was supposed to front $1 million of the budget, backed out just before shooting was set to begin, sending producer Robert Shaye scrambling to find funding from other sources. Just two weeks into production, they were literally broke and had no money to pay the crew, so line producer John H. Burrows put it all on his credit card. Eventually, Shaye brokered a deal with Media Home Entertainment and convinced Smart Egg to cover the last $200,000 of the budget. Still, New Line was in dire straits by the time production wrapped. But the success of Nightmare on Elm Street saved New Line from bankruptcy, and the studio was afterward jokingly referred to as “The House that Freddy Built.” Nightmare made $25.5 million (almost $64 million today) on a $1.8 million budget (or $4.5 million today).

12. Its release was held hostage.

As it turns out, when you don’t have money and you’re about to declare bankruptcy, it’s hard to pay contractors and partners. Just days before the movie was slated to be released, the processing lab that had the film negative said it was keeping the film as they hadn’t been paid. At the last minute, Shaye was able to negotiate a deal that satisfied the lab and the movie was released on time.

13. It was Johnny Depp’s first movie role.

The young actor was so self-conscious and uncertain about his performance that he sometimes had to be reassured on set that he was doing a fine job. One of the main reasons Depp beat out the competition to land the role of Glen was because Wes Craven’s daughter declared him “dreamy.” Along the names on that list of competition? Charlie Sheen, John Cusack, Brad Pitt, Kiefer Sutherland, Nicolas Cage, and C. Thomas Howell.

14. The melting staircase scene was achieved with pancake mix.

Heather Langenkamp has said the melting staircase scene was achieved by using pancake mix – Bisquick, to be exact. Later, she added that mushroom soup was one of the ingredients in the mixture. However, Wes Craven himself. says it used a mixture of oatmeal and glue. Whatever they used, they achieved a really gross practical effect, so well done.

15. Robert Englund based Freddy’s unique walk and mannerisms from a number of sources.

In interviews, Englund has said he partly based the physicality of Freddy on Klaus Kinski’s performance in Werner Herzog’s 1979 film Nosferatu the Vampyre. There’s also a bit of mobster in his swagger, as well: When Englund put the fedora on and looked in the mirror, he thought Freddy’s silhouette looked a bit like a gangster so he decided to give Freddy a swagger that mimicked James Cagney in his famous gangster roles. As for Freddy’s unusual, sideways sidling walk, Englund based it on surfers standing sideways on a surfboard.

16. The glove informed his peculiar stance, too.

If you go back and watch the original film, you’ll notice that Freddy has a peculiar slant-shouldered stance. Turns out this is by design – sort of. While there was a stunt glove used for safety, the full glove with the real knives was extremely heavy. So much so that when Englund wore it, he found he was subconsciously dropping his right shoulder due to the weight of the glove pulling it down. So he worked that into his stance, turning it into the equivalent of a gunslinger dropping his shoulder toward a holster on his hip.

17. Freddy Krueger has under seven minutes of screen time in the entire film.

It seems impossible, but it’s true: Robert Englund only appeared in the film for seven minutes. That Freddy is still so terrifying and compelling is a testament to Wes Craven’s instinctive understanding that what is unseen is far more terrifying than what is seen, and to Englund’s iconic performance with the little time he had. He’s also never once seen in daylight, which adds to his sinister persona.

18. Freddy was originally envisioned to be a silent serial killer.

At the time, Wes Craven intended for Freddy to be in the vein of other slashers of the era like Michael Myers and Jason Voorhees. But Englund’s natural tendencies gravitated toward taunts and wisecracks and Freddy became a blackly comedic figure, particularly in the sequels.

19. Heather Langenkamp injured herself on set and it made it into the movie.

During the scene where Nancy is running toward her house with Freddy right behind her, you can see Nancy limping as she runs. However, this wasn’t an acting choice on Langenkamp’s part but the result of her actually having cut her foot open badly enough to require stitches. She went to the hospital, got stitched up, and was back to continue shooting in just a few hours. If you look closely, you can see the bandage on her foot in the last shot of the melting stairs sequence.

20. Langenkamp’s then-boyfriend came up with the famous theme song

Every 80s kid can recite the Freddy Krueger nursery rhyme:

One, two, Freddy’s coming for you
Three, four, better lock your door
Five, six, grab your crucifix
Seven, eight, gonna stay up late
Nine, ten, never sleep again

The terrifying lyrics set to the simple tune of “One, Two, Buckle My Shoe” makes it one of the most memorable little ditties in horror history. The credit for it goes to Langenkamp’s boyfriend at the time, Alan Pasqua, who was a musician. He composed the music for the words and the film’s composer Charles Bernstein liked the result so much he worked Pasqua’s contribution into the movie and it became Freddy’s recurring theme.

A Nightmare on Elm Street is currently in theaters.

Get tickets to A Nightmare on Elm Street.