At first, Yung Lean's Yoshi City video is just like any other young up-and-coming hip-hopper's. The teenage rapper hangs out of a moving car surrounded by his crew. There's a phone in his hand, a fag in his mouth. But the familiar rap tropes are scrambled into a kind of super-internet pastiche. His ride's a sensible Smart car; his crew, sullen adolescents from Stockholm who call themselves the Sad Boys. Beside him sits not Cristal but a bright pink My Little Pony. And there's Lean himself: a chubby-cheeked cherub, more Directioner than Chicago South Side, who deadpans about being a "lonely cloud". "We just thought it was funny," he says later. "I'm not really into My Little Pony, I'm not a 'Brony', just to clear that up."

You'd be right to wonder whether this is all elaborate parody, as many did when Yung Lean started uploading videos in February 2013. In his first homemade clip he smoked cigarettes in the snow while drawling lazily in AutoTune over a trap beat. The track was called Greygoose, after the vodka. Middle of the range brands like Arizona Iced Tea, Bacardi and The North Face also pepper his lyrics, alongside childish pop culture references like The Smurfs, Mario Kart and Harry Potter.

But follow-up tracks Ginseng Strip 2002, Hurt and Kyoto suggested it wasn't just a piss-take. They racked up millions of views, creating a Sad Boys fanbase that wasn't just there for the ironic videos. Yung Lean had tapped into millennial ennui, and by the time he turned 18 this July he'd played sold-out venues across the US to breathless reviews from the New York Times and the New Yorker. Indeed, no less a cultural arbiter than Justin Bieber turned up backstage to have his picture taken with the Sad Boys.

Back at his family home in Sweden, Yung Lean, born Jonatan Leandoer Håstad, is happy that the laughter's stopped. "When I first broke out, everyone was like: 'OK, so is this a joke?'" he says. "They had to wait until I sold out shows before newspapers started writing about it. It's the same in Sweden. They're scared to say it's good. They say it's a joke until I prove them wrong."

He puts the confusion down to the fact that the Sad Boys' music doesn't fit into existing scenes. "I think people are scared of progress and change," he says. "But I'm proud we're not repeating anything." He's been grouped with self-consciously weird US rappers Lil B and Lil Ugly Mane in the past but dismisses the idea that they're his influences. "That's simple shit," he snorts. "You don't even have to listen to my music to get those references. Nowadays I'd say I'm more inspired by Madonna and 50 Cent." Material Girls cavorting in the Candy Shop? These Sad Boys are having the last laugh.

Yung Lean & Sad Boys play The Roadhouse, Manchester, Tue; Audio, Glasgow, Wed; The Garage, N5, Thu



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