Universal’s classic monsters are about to return in a big way. The studio is currently planning remakes of many of its iconic horror films like The Mummy, The Wolf Man, The Invisible Man and The Creature From the Black Lagoon, all of which will take place in the same universe. Clearly they’re hoping to emulate the success of Marvel, but to be fair, Universal was doing the whole cinematic universe thing long before it was cool. From the 1930s into the early 1950s, they were pumping out monster sequel after monster sequel leading into crossover events like Frankenstein Meets the Wolf Man and House of Dracula. Looking back, the series as a whole is quite messy, but that only makes it more fun for hardcore fans to discuss, and stories from behind the scenes are utterly fascinating. Here are 15 fun facts about the original Universal Monsters franchise.

15. The writer of The Mummy was present for the opening of Tutankhamun’s tomb

Most fans know that The Mummy (1932) was inspired by the real life opening of Tutankhamun’s tomb, but not in the sense that the screenwriter read about it in a book and went from there. No, the movie was written by a former journalist who, a decade earlier, covered the event himself.

Before landing a gig in Hollywood, The Mummy writer John Lloyd Balderston was a foreign correspondent for New York World, and he wrote extensively about the opening of Tutankhamun’s tomb in 1922. Originally, Universal’s film was going to follow a 300-year-old magician living in San Francisco, but when Balderston joined the project, he moved the story to Egypt, renamed the main character Imhotep, and focused in on the Scroll of Thoth.

Balderston also worked on Frankenstein, Dracula, Bride of Frankenstein, and Dracula’s Daughter, so he’s easily one of the most significant creative minds of the Universal Monsters series. Considering how influential all the aforementioned movies were, who knows if the horror genre itself would be the same had Balderston not taken that reporting job at New York World.

14. The Mummy’s eyes were blacked out frame by frame in The Mummy’s Hand

The antagonist in The Mummy’s Hand has a unique look to him, as evidenced in closeups where his eyes are totally black. It’s simple and effective, giving the character an otherworldly touch. This would be easy enough to accomplish today, but keep in mind that this was 1940, so the special effect was no cinch. During every single closeup of Kharis in The Mummy’s Hand, his eyes and mouth had to be manually blackened frame-by-frame. To put that in perspective, a 10 second shot in a movie generally contains 240 individual frames. That’s an extraordinary amount of additional work just to make the villain ever-so-slightly creepier.

13. Wallace Ford’s character inexplicably changes names

Back in the 1940s, before the advent of the Internet and home video, filmmakers didn’t care as much about continuity as they do now. After all, who was going to remember minor details about a 60-minute movie they saw years earlier and never again? This was especially the case in the Universal Monsters franchise, as names of characters and locations change all the time for no reason. For instance, Wallace Ford plays a man named Babe Jenson in The Mummy’s Hand, but in the sequel, The Mummy’s Tomb, he is now referred to as Babe Hanson. No explanation is given. Maybe he got remarried to someone who coincidentally had an extremely similar last name?

There’s another example in Son of Frankenstein: the character of Ygor suddenly becomes Igor in this sequel. You can only really tell the difference by looking at the credits, so it was probably just a typo, and in the next film, his name goes back to Ygor again. How about Frankenstein Meets the Wolf Man? The town is called Vasaria, but in House of Frankenstein, which takes place in the same continuity, it’s now Visaria instead. In 2016, this sounds totally ridiculous; imagine going to see Avatar 2 and the name of the planet is now Pandoria. But in the 1940s, you would need the most exceptional memory on the planet to pick up on these trivial mistakes.

12. Applying makeup took basically the entire day

For just about every one of the Universal monster movies, applying the makeup took an insanely long amount time. Starting off with The Mummy, transforming Boris Karloff into the creature was an eight hour process. Makeup artist Jack Pierce would begin working on Karloff at 11:00 AM and finish at 7:00 PM, with shooting then lasting from 7:00 PM until 2:00 AM. Then, after filming, it took another two hours to get the makeup off. Karloff has called this “the most trying ordeal I [had] ever endured,” although luckily for him, he at least doesn’t wear the iconic bandages for the majority of The Mummy.

In Frankenstein, the makeup application took four hours, half the time as in The Mummy, but in this case it had to be done every single day. This costume weighed nearly 50 pounds, and the movie was filmed during the summer, so we can only imagine what was going through Karloff’s head at the end of a 14-hour day. For The Wolf Man, putting on the makeup took six hours, and another three were required to get it off at the conclusion of shooting. Imagine sitting in a chair for six straight hours having rubber prosthetics and yak hairs slowly applied to your face. Not exactly glamorous, and Lon Chaney Jr. and Jack Pierce reportedly hated each other by the time production ended.

11. Most of the Mummy movies take place in the future

Every Mummy movie takes place a few years after the previous one, though rarely is it stated what year we’re in specifically. That’s probably because when you actually add up all the time skips, the sequels go hilariously far into the future considering that they all have such an antiquated look. The original Mummy opens in 1921 before jumping ahead 10 years to 1931. The Mummy’s Hand skips another decade, unfolding during May of 1940. In The Mummy’s Tomb, it’s said that 30 years have passed, so we’re now all the way in 1970. Despite that, the characters continuously reference World War II as an ongoing event, as if the screenwriters just forgot what time period they were supposed to be in. Or did they think World War II would stretch into the 1970s?

And it keeps going! The Mummy’s Ghost is set two years later, in 1972. That’s not so bad, but just when we thought the massive time jumps may come to an end, The Mummy’s Curse takes place 25 years in the future. That means we are now in the year 1997, yet the entire film looks like it’s set in the 1800s, and the fact that it is now close to the turn of the century has absolutely no impact on the way director Leslie Goodwins approaches the story. Just look at the picture above from The Mummy’s Curse and try to imagine it occurring during the same year that Titanic was released in theaters, Bill Clinton began his second term, and everyone was playing Nintendo 64.

10. A line in Frankenstein was missing for years

During the famous “It’s alive” scene in Frankenstein, the doctor goes on to say, “In the name of God, now I know what it feels like to be God!” That line is on all the current home video releases, but the audio was missing for a period of time. It was present during the 1931 premiere, but when Universal rereleased the film in the late 1930s, the censors decided this dialogue was sacrilegious and needed to be removed. In the new version, Dr. Frankenstein can still be seen mouthing the words, but his lines are drowned out by thunder. Well, that’s one way to deal with the issue.

On the earliest video releases, the line was kind of restored, but it’s very hard to hear because, believe it or not, nobody had a good recording of the original audio. It was only years later when a clean version was found on a Vitaphone disc that the dialogue was inserted back in perfectly, and now it’s not even noticeable that anything was changed. Thanks, Vitaphone!

9. The Bride of Frankenstein was inspired by swan behavior

Even though she’s such an iconic character and is considered to be an official member of the Universal Monsters lineup, The Bride of Frankenstein sure doesn’t do much. She literally only has five minutes of screentime before she dies and never returns in any sequel. Has any other character made such an impression in five minutes? The Bride mostly jerks her head about and hisses, and as it turns out, actress Elsa Lanchester based this on the swans she would observe at Regent’s Park in London. “They’re really very nasty creatures,” she once said. And just so the audio would sound even stranger, her hissing sounds were run backwards in post-production.

8. Boris Karloff didn’t want Frankenstein’s Monster to speak in the sequel

After being mute throughout the first Frankenstein, the monster learns to speak in the sequel, Bride of Frankenstein. Boris Karloff really hated that idea, arguing that it ruins the charm of the character. He explained, “Speech! Stupid! My argument was that if the monster had any impact or charm, it was because he was inarticulate – this great, lumbering, inarticulate creature.” Another side-effect of this development was that the monster’s cheeks now appear less hollow. That’s because during speaking scenes Karloff had to keep his dental plate in, whereas he took it out during production of the original. Karloff would ultimately get his way, though, as in the very next movie, the monster goes back to being mute.

7. James Whale didn’t want to make a Frankenstein sequel

Speaking of Bride of Frankenstein objections, director James Whale objected to the entire concept of making a Frankenstein sequel, saying that he had “squeezed the idea try.” He had a point, to be fair, but Universal was thinking about a follow-up as early as 1931, which explains the last-minute decision to have Henry survive the movie.

The studio really wanted Whale on board for part two, especially after his next film, The Invisible Man, was a huge hit. Whale still wasn’t into the idea, but he finally agreed to sign on in late 1934. The studio was apparently confident he’d come around; they were putting out press releases about the sequel, then titled The Return of Frankenstein, as early as 1933.

When Whale came aboard, there were already several versions of the script that had been completed. He was not a fan of them, reportedly saying of the existing screenplay, “It stinks to heaven.” It wasn’t until Whale hired John L. Balderston, who worked on an early draft of the first movie, that Frankenstein having a mate was delved into, as this is mentioned briefly in the original novel.

6. The Invisible Man effect was accomplished using black velvet

The special effects in The Invisible Man can be taken for granted today considering anyone can pull them off using Final Cut and an iPhone. But imagine how hard it was in 1933, not too long after motion pictures were invented, to make an actor’s skin seem to be invisible. How do you make that happen with such primitive technology? Visual effects artists John Fulton himself was unsure it could be done, saying in an interview that the script “bristled with difficult special process scenes, and I wondered if, even with our modern process techniques, we could possibly make all the amazing scenes called for.”

Fulton came up with a novel solution. First, the scene was shot with all the other actors, who just had to pretend the Invisible Man was there. Then, the filmmakers had Claude Rains wear a black velvet suit and act on a completely black velvet set, combining that with a matte painting. If you want to get technical with it, Fulton explained, “From this negative we made a print and a dupe negative, which we intensified to serve as mattes for optical printing. Then with an ordinary printer we proceeded to make our composite: first we printed from the positive of the background and normal action, using the intensified negative matte to mask off the area where our invisible man’s clothing was to move. Then we printed again, using the positive matte to shield the area already printed and thus printing in the moving clothes from our ‘trick’ negative.”

That is a lot of work, huh? Though some of the Universal movies are rather dated, The Invisible Man still looks shockingly good for a film made over 80 years ago, and that’s all thanks to the magnificent work of the brilliant John Fulton.

5. Frankenstein’s Monster originally had dialogue in Frankenstein Meets the Wolf Man

In the script for Frankenstein Meets the Wolf Man, Frankenstein’s Monster had dialogue all throughout, but every single line was cut from the finished product. This was clearly done at the last minute, as there are several scenes where you can still see Bela Lugosi’s mouth moving without any words coming out. What happened? Apparently, test screening audiences all burst out laughing when they heard Lugosi speaking as the monster with a Hungarian accent. They couldn’t take it seriously, which is odd considering Lugosi already spoke as the monster in the previous film, Ghost of Frankenstein. In that case he was performing as Ygor trapped inside the monster’s body, though.

The original Frankenstein Meets the Wolf Man script also recapped for audiences why the monster is behaving so strangely and outstretching his arms (he went blind in Ghost of Frankenstein), but this was part of the dialogue that was removed, leaving a lot of viewers confused. Wouldn’t it be better to have them laugh at an accent than to have them not know what the heck is going on in the story? Evidently Universal didn’t think so.

4. Son of Dracula is the first time anyone turns into a bat

What was the first movie in the Universal Monsters franchise to depict someone turning into a bat? Obviously Dracula with Bela Lugosi, right? Nope. It wasn’t until 13 years after the release of the original that this iconic image was put to screen. In Dracula, Bela Lugosi’s character does indeed turn into a bat at one point in the film, but the transformation does not take place in front of the camera. It finally happens in Son of Dracula, the third film in the series. The effect was pulled off once again by John Fulton, the man who came up with the crazy black velvet trick on The Invisible Man. The bat transformation would soon become a staple of every vampire movie, despite the fact that it is completely absent from the first two Dracula installments.

3. There are four Frankenstein Monsters in House of Dracula

House of Dracula is one of Universal’s greatest crossover movies, featuring Dracula, the Wolf Man and the Frankenstein Monster. But it doesn’t just include one Frankenstein Monster; there are actually four of them in the film. The main actor playing the monster is Glenn Strange, but there’s also brief footage of Lon Chaney Jr’s monster from The Ghost of Frankenstein. Then there’s Boris Karloff as the monster in a scene where footage is lifted from The Bride of Frankenstein. Finally, the finale features clips from The Ghost of Frankenstein in which the monster is played by Lon Chaney Jr. and his stunt double, Eddie Parker. To summarize, between Strange, Chaney Jr., Karloff and Parker, the are nearly enough Frankenstein Monsters in this movie alone to make up an Avengers-style team.

2. The guy playing the Creature from the Black Lagoon could barely see anything

Being covered in pounds of makeup during filming was a pain, but wearing monster suits presented their own challenges. On Creature from The Black Lagoon, Ricou Browning had to wear a massive creature costume that overheated instantly and made it so that he could not sit down for the entire 14-hour work day. In addition how uncomfortable the suit was, it was virtually impossible to see in it. Browning once said that he had an incredibly hard time making out his surroundings during the entire production.

He explained, “I didn’t wear any goggles or [a] facemask and the eye of the suit sat about an inch from my eye…it’s kind of like looking through a keyhole with blurred vision, so it was difficult seeing.”

In fact, that lead to some dangerous mistakes on set. During the cave sequence, Browning accidentally knocked Julie Adams’ head into the artificial rocks. Going back and watching that scene, then, it’s not as scary if we view it as an overworked, tired actor struggling to navigate through a fake cave set while a terrified actress prays her co-star doesn’t severely injure her in the process.

1. Universal nearly stopped making monster movies a few years in

The original Universal Monsters series goes into the 1950s, but it almost ended much earlier than that. After 1936, the studio dropped monster films from its production lineup completely, and that could have been the end of it. But one theater in Los Angeles can be credited for bringing Dracula, Frankenstein, the Wolf Man and the rest of the gang out of retirement.

In 1938, the owner of the Regina Theatre in Beverly Hills was struggling to stay in business, and so he made a deal to show a triple feature of Dracula, Frankenstein and Son of Kong. The intention was to have this feature run for only four days, but it was an unexpected hit, with lines around the block for days. The Motion Picture Daily reported at the time, “Beverly Hills traffic stopped around the house the first night. The police helped keep the customers in line…The grosses had the Regina cashier dizzy.” Soon enough, the four-day event was extended indefinitely.

Other theaters began getting in on the madness, and Universal realized that there was an enormous demand for these monsters to return to the big screen. Instantly, they put additional sequels into production, and Son of Frankenstein was released in January of 1939. Yeah, they didn’t wait very long. It’s unclear if Universal would have ever resumed production on monster movies otherwise, so 1940s horror was dramatically shaped by one random theater owner attempting to make a quick buck.