Simpsons' new beginning has Banksy's name written all over it

When the clouds above Springfield parted as always on Sunday night, American fans sitting down to another episode of The Simpsons got their first inkling that all was not as it should be: a black crow, carrying what appeared to be a dead rat, flapping across the screen with a mad glint in its eyes.

The show's opening sequence is renowned for its variety, but what followed was like nothing it has featured before. It had mythical beasts in bondage, starving sweatshop workers, and an abundance of human bones, all in service of a ferocious satire of the Fox network's working methods. The explanation? For the first time, the show's creators had allowed an outsider to storyboard an entire sequence for the show. And by choosing Banksy, they all but guaranteed that the results would be controversial.

Banksy is far from the first celebrity to contribute to The Simpsons – everyone from Tony Blair to Ricky Gervais has done it before. But no one has worked on the show's animation in quite the same way. The selection of the British street artist was swiftly made apparent by the way his name appeared scrawled over a billboard of Krusty the Clown.

If the producers were hoping for something out of the ordinary, they ended up worrying they had bitten off more than they could chew. "I'd be lying if I said I didn't think about it for a little bit," said Al Jean, executive producer of The Simpsons, of fears that the sequence would land him in hot water. "I haven't been fired yet, so that's a good sign."

So acerbic is Banksy's satire of the show's production that the animators tasked with putting his vision into action threatened to walk out before rendering it for broadcast. "This is what you get when you outsource," joked Jean.

The sequence proceeds with relative normalcy – Bart writing "I must not write all over the walls" all over the walls, for instance – and runs on to the usual conclusion as the Simpsons settle down on their couch. Then, all of a sudden, the shot zooms out to show the image appearing on a TV in some hellish sweatshop in Asia. The location is not specified, but it would not be unreasonable to guess at South Korea, where Fox has outsourced much of the show's production.

That this is not a happy place is immediately clear. Kittens are shredded to provide stuffing for Bart Simpson dolls, which are tossed into a barrow hauled by a stricken-looking panda bear. A unicorn stands shackled – until it collapses – as workers use its single horn to punch holes into the middle of Simpsons DVDs. It all ends with a ghastly image in black and grey of the familiar 20th Century Fox logo – except surrounded by barbed wire and prison look-out towers.

That the sequence caused some ruffled feathers is no surprise. But maybe it was worth the tumult. The judges at Gawker, the New York-based gossip site, found Sunday's episode refreshing and funny in the best tradition of the long-running programme, which some feel has gone a little off the boil of late. "Like most Banksy art-things, it was 'political'," they offered. "But it was also funnier than anything that's been on The Simpsons in a long time."