Maybe you’ve heard the one about the girl with a spider bite on her cheek. Thinking it’s a pimple, she tries to pop it — and out pour hundreds of baby spiders that have been incubating in her face.

That urban legend turns up as “The Red Spot,” one of dozens of gruesome tales from “Scary Stories To Tell in the Dark.” Alvin Schwartz’s three-book series of horror stories, with haunting illustrations by Stephen Gammell, has been terrifying young readers since the first installment arrived in 1981.

Now director André Øvredal has put a generation’s squirmiest, most disturbing childhood memories on film in “Scary Stories To Tell in the Dark,” out Friday.

How does one do justice to a legend? Øvredal, a Norwegian, started by reading.

“The first thing I did was buy these books and read them and research how big of a cultural impact they had on Americans growing up in the ’80s and ’90s and even today,” the director tells The Post. “There are so many people who know the stories. Schwartz concocted something that stirred the American children’s psyche.”

The director’s critically acclaimed first movie, 2010’s “Trollhunter,” was an original screenplay he wrote himself, so the 46-year-old filmmaker had an entirely different challenge in front of him with the “Scary Stories” adaptation. Luckily, he had an ace: Guillermo del Toro was producing. And if anyone knows indelibly scary imagery, it’s the Oscar-winning del Toro, whose 2006 film “Pan’s Labyrinth” is still the standard-bearer for creepy creatures.

“I’m so proud now of being part of Guillermo’s legacy of monsters and creatures,” says Øvredal. “And I can’t tell you how many tweets I’ve seen about people talking about how the drawings by Gammel scared them witless as kids.”

Exhibit A: The Pale Lady, a fleshy figure with a misshapen and smiling face who, in the film, plods slowly but relentlessly down a red-lit hallway. Then there’s the Jangly Man, a pile of limbs and a screaming head that assembles and deconstructs itself while chasing its prey.

One of the first characters to pop up in the film is a scarecrow named Harold, who comes to life and chases down a jock who’s been hitting him mindlessly every time he passes.

“Scarecrows are scary!” says Øvredal, whose rendition of Harold has cockroaches crawling out of its eye sockets, a gaping hole through its midsection and a sagging, skin-like visage. “Maybe it’s the idea of an inanimate object that’s so humanlike,” he adds. Much like the narrative structure of many of the stories, Øvredal says he aims to “use the feeling of dread as long as I can, to stretch out the audience’s tension — and then, at a certain point, release that with a punch.”

One psychological legacy of Schwartz’s books, he thinks, can be found right in front of us — on Twitter: “On social media, things can be manipulated and propelled into stories that have no grounding in reality — but people believe them.”

Scary, indeed.