In 1960’s Where the Boys Are, four college girls (including the squeaky-clean Connie Francis) drove to Fort Lauderdale for some spring break fun. In Harmony Korine’s Spring Breakers, four college girls (including Disney alumni Selena Gomez and Vanessa Hudgens) rob a restaurant in order to pay for their own spring break trip, now held in St. Petersburg.

It’s pretty clear things have changed — and how. Instead of beach blanket bingos, spring break is now a never-ending series of parties and orgies, fueled by booze and drugs, scored to Skrillex and hip-hop.

And Korine plunges you into the bacchanal, using his camera to swim through oceans of bikinis and shorts and topless young people behaving irresponsibly. This is not planet Earth, you think. This is a scary alternate reality, much rawer and crazier than the spring break images made familiar by MTV.

“My films have always tried to push the limits and steer something toward experiential — something that is like a drug hallucination, something with transcendence and a peak,” says Korine, 40, who became famous for his notorious screenplay for 1995’s Kids and has gone on to direct his own films ( Gummo, Julien Donkey-Boy, Trash Humpers).

“I didn’t want to make a movie that was purely a spring break movie,” he says. “I wanted spring break to be representative of a dream for these girls — a backdrop. What I was really interested in was the stuff past the obvious debauchery and iconography. I wanted to see what happened when these characters leave the beach and its corporate trappings and step into the criminal underbelly of the scene — the cocaine houses, the violence, the rusted yachts. I’m not trying to saying what you see in this movie is the truth. It’s more of a tone poem — a hyper-violent, hyper-sexualized reinterpretation of that culture.”

Harmony’s wife Rachel, who plays one of the four party girls, says finding the balance between humor and danger was tricky.

“It would have been very easy for the movie to veer into parody,” she says. “But you have to push it far enough so the line between fantasy and reality disappears. It was important to capture the feeling these kids have when are on spring break, they’re drunk or high or whatever and they wake up the next morning thinking ‘Whoa, did I really do that?’ When [James] Franco’s character arrives, things start to get more serious. He ignites them to go deeper into themselves — to a very deranged place.”

Franco’s hysterical performance as Alien, the cornrowed, gold-toothed, fast-talking drug dealer who bails the four girls out of jail and leads them down a path of crime, is astonishing: It’s the kind of performance people start quoting the moment they leave the theater.

“I had been talking to him for a while about doing a movie,” Korine says. “He’s a handsome guy, so he gets leading roles, but I thought he was wild enough and out there enough to inhabit more extreme characters. We developed Alien for a year, a kind of gangster-mystic, a cultural mash-up. He’s equal parts sociopath and clown. He’s pure charisma and wildness.”

He is also a good singer. In one of the most indelible moments of Spring Breakers, Franco sits at a piano and plays a lovely rendition of Britney Spears’ Everytime while two girls wearing bikinis and pink ski masks and sporting shotguns dance along.

It’s a classic Korine image — something that makes no discernable sense but sears itself into your memory, defying you to invest it with meaning.

“These things come from my dreams,” he says. “It comes from wanting to create images that are inexplicable, that are beyond a simple articulation of an idea. You want to get beyond things that have simple logic. You want things that are more transcendent. That scene was an attempt to create something that’s like a pop poem — a fever dream that exists in a physical way and you can’t stop thinking about it.”