Independence Day wasn’t the only star-studded alien invasion flick to come out in 1996. That year, Tim Burton saluted the campy sci-fi epics of decades past with his big-budget B-movie Mars Attacks! Here are 10 facts about the cult classic that’ll blow your mind—just like a certain Slim Whitman song.

1. IT’S BASED ON A CONTROVERSIAL SET OF TRADING CARDS.

In 1962, the Topps Company, Inc.—best known for its iconic baseball cards—infuriated quite a lot of parents by releasing some subversive new collectibles. Mars Attacks! was a bubble gum trading card series that chronicled a fictitious alien invasion. In total, there were 55 cards, each adorned with a grim painting by comic book artist Norman Saunders, and many of these images were downright unsettling.

One card showed a giant insect decapitating naked women in a shower room. Another featured a dog being vaporized right in front of its owner—a small child. Needless to say, Topps soon found itself in hot water over these. “We started to get some bad publicity,” recalls series co-creator Len Brown. “[People asked] ‘How could you put out such gory trading cards for little kids?’” Newspaper editorials slammed the franchise, a district attorney called Topps president Joel Shorin to complain, and angry letters flooded the company’s mailrooms.

Within months, the set was discontinued. But America hadn’t seen the last of Mars Attacks! Despite all the controversy, these gruesome cards won an underground following, and, in 1984, the original 55 were reissued. Since then, Topps has put forth dozens of Mars Attacks! products, from new cards to comic books to action figures. Meanwhile, first-edition 1962 cards have become serious collector’s items: In 2008, a mint condition copy of just one card sold for $3600 at an auction sale.

2. BURTON WANTED HIS MARTIANS TO BE ANIMATED VIA STOP-MOTION.

The concept of a Mars Attacks! movie first surfaced in 1985, but development wouldn’t begin in earnest until 1994, when screenwriter John Gems and director Tim Burton got involved with the project. To bring the aliens to life, Burton intended to utilize stop-motion animation, something he’s “always [loved] and always will.”

Early in pre-production, a set of 12-inch articulated Martian models were built for testing purposes. At first, Burton’s plan was to have these animated in front of a blue screen. They would then be inserted digitally onto miniature sets by the artists at Industrial Light and Magic (ILM). Ultimately, though, Burton decided to abandon the stop-motion approach when ILM presented him with some impressive screen tests featuring computer-animated aliens.

Despite this, Mars Attacks! still pays tribute to the older effects technique. At Burton’s instruction, ILM animated the digital extraterrestrials as if they were stop motion puppets. This is why the Martians move a bit more rigidly than did most contemporary CG characters, such as the dinosaurs in Jurassic Park (1993).

3. THE ALIENS’ LOOK WAS INSPIRED BY SOME MAGAZINE ART AND A CLASSIC SCI-FI FLICK.

When Len Brown and his Topps colleague Woody Gelman created the trading card series, they decided to give their Martians a bold, grotesque design. “Somehow, the cliché of little green men from another planet just didn’t seem dramatic enough,” Brown says. “My love of old comic books brought to mind an issue of E.C.’s Weird Science from 1952, with a striking cover illustration by Wally Wood."

As Brown explains, "The cover depicted UFOs landing on the Earth and releasing a group of large-brained, foreboding aliens onto our world. The invaders were pretty hideous, like nothing I had ever seen before—until in 1955 when I saw a similar-looking creature in the Universal movie This Island Earth.” (Cult cinema fans will recognize this as the film that was riffed in 1996’s Mystery Science Theater 3000: The Movie.) These twin sources provided the inspiration for the physical appearance of the aliens that popped up on Topps’ cards. Decades later, the Mars Attacks! movie reproduced this design quite faithfully. Hey if it isn’t broken, don’t fix it…

4. WHY DID SO MANY CELEBRITIES JOIN THE CAST? THANK JACK NICHOLSON.

Let’s do a quick head count. Glenn Close, Martin Short, Pierce Brosnan, Danny DeVito, Michael J. Fox, and Sarah Jessica Parker are just a few of the big names on this movie’s mile-long list of stars. And yet, when the casting process began, Mars Attacks! struggled to attract any players with serious marquee value. Gems blames this on the fact that most of its characters either die in some cartoonish manner or end up disfigured.

“Agents didn’t want to see their star clients playing loser roles, and a lot of big acts passed on the project,” he says. “At one point, we thought we were going to have to cancel the film. The guy who saved our butt was Jack Nicholson.” According to Burton, the Academy Award-winner was enthusiastic about joining Mars Attacks! from the very start. After sending Nicholson the script, Burton gave him a call while location-scouting. “Which part would you like to do?” asked the director. “How about all of them?” Nicholson replied.

In the end, he was double-cast as President Dale and a sleazy Vegas businessman. Once word got around that Nicholson would be involved, other celebs lined up to join the ensemble. “We started getting requests from more stars than there were parts for,” Gems notes. “It was like a tidal wave when Jack came on.”

5. THE “MARTIAN GIRL” WIG GAVE ACTRESS LISA MARIE A NASTY SCAR.

“I mean, it was instant torture,” Marie said in a 2015 interview. The movie’s femme fatale rocks a bulbous hairdo comprised of two separate blonde wigs—made with real human hair—that were stitched together. Given its considerable weight, wearing this apparatus wasn’t a pleasant experience. “I have a scar from the wig,” Marie revealed, “I have a hole in my head from that damn wig.” Still, like a true professional, she soldiered on despite the discomfort and remembers her character fondly. “It’s always worth it,” added the actress. “[I do] whatever it takes."

6. FOOTAGE OF A REAL CASINO’S DESTRUCTION WAS USED IN THE MOVIE.

On November 7, 1995, the Landmark Hotel and Casino—an oddly-shaped 31-story building in Paradise, Nevada—was brought down via controlled implosion. The event was filmed and this footage was later incorporated into the assault on Las Vegas scene in Mars Attacks!

7. DANNY ELFMAN’S SCORE WAS A MUSICAL TRIBUTE TO THE GOLDEN AGE OF SCI-FI CINEMA.

Elfman—who’d provided the soundtrack for every previous Tim Burton film with the exception of Ed Wood (1994)—gave Mars Attacks! some decidedly old-school background music. “The goal was to invoke the ‘50s and that sci-fi sound that Tim and I both grew up on,” he told Vulture.

To pull this off, he made liberal use of one of history’s first electronic instruments, the theremin. Invented by (and named after) Russian scientist Leon Theremin, it produces an eerie, humming wail. Throughout the 1950s, film composers embraced the aural gadget as a perfect mood-setter for science fiction and horror pictures.

Due to its usage in such movies as The Day the Earth Stood Still and The Thing From Another World (both released in 1951), the public came to associate theremins with stories about extraterrestrial visitors. Elfman deliberately capitalized on this by using said instrument as a key component of the ominous “alien march” theme in his Mars Attacks! score.

8. DEPENDING ON WHO YOU ASK, THE ALIENS’ SQUAWKS WERE EITHER THE PRODUCT OF IMPROVISATION OR “PLACEHOLDER DIALOGUE."

The Martians in this film mainly communicate with a series of duck-like “Ack! Ack! Ack!” noises. Burton traces their monosyllabic language back to one fateful day in pre-production. “We did a storyboard reel using a cheap tape recorder—and we don’t even remember who did it—someone just [said] ‘yak-yak, yak-yak’ when it came time for the Martians to speak,” he told the Chicago Tribune.

Burton maintains that this improvised squawk “ended up kind of sticking. It just seemed like their voice.” On the other hand, two of the film’s uncredited screenwriters believe that they devised this particular sound effect with nary a recorder in sight. While the script was being fine-tuned, Scott Alexander and Larry Karaszewski—the scribes behind Burton’s Ed Wood biopic—made some heavy revisions to Gem’s original screenplay. The pair claims that the “Ack! Ack! Ack!” shtick was (sort of) their idea. “That was all us,” Karaszewski declares.

Supposedly, while Gem’s script often called for the aliens to talk, he didn’t give them any actual dialogue. Alexander then started typing “Ack!” over and over again as a verbal placeholder. All the while, neither man suspected that the utterance would make its way into the finished movie. “We didn’t know Tim was just going to take that and use it,” Karaszewski says.

9. INDEPENDENCE DAY OWES ITS TITLE—AND PART OF ITS PREMISE—TO MARS ATTACKS!

While Burton toiled away on Mars Attacks!, Dean Devlin and Roland Emmerich were writing an alien invasion movie of their own, but theirs was to have a more serious tone. The duo knew that both pictures would be released at some point in the summer of 1996.

“I said to Dean, we can’t do our film after a parody comes out. We had to beat [Burton] to it,” Emmerich recently said in an interview with The Guardian. “If it came out on the 4 July weekend, we would beat Mars Attacks!, which was coming out in August. So we wrote the concept around the release date. Dean said: ‘Let’s just call it Independence Day; we can come up with something better later.” The rest is history.

10. HOWARD STERN HAS IMPLIED THAT THE ENDING WAS LIFTED FROM ONE OF HIS RADIO SKITS.

To these big-brained Martians, nuclear weapons are harmless, but Slim Whitman’s yodeling is deadly. At the end of Mars Attacks!, the country singer’s 1952 hit “Indian Love Call” is used to burst the aliens’ noggins with grim efficiency. Upon seeing this climax unfold, Howard Stern had the strangest feeling of déjà vu.

In 1982, the radio personality had done a sketch with an almost identical premise for the New York station WNBC. The title of Stern’s bit? “Slim Whitman Versus the Midget Aliens From Mars.” Years later, when he got around to watching Mars Attacks!, Stern couldn’t resist pointing out the similarities on the air. And during a subsequent interview with Burton for The Howard Stern Show, he raised the subject again. “I wouldn’t sue you because I love you too much,” Stern said, “but I don’t think it’s a coincidence.” Burton, for his part, called the parallels “surreal” and noted that “something about Slim’s voice is very sonic.”