Banksy artwork self-destructs moments after selling at auction for $1.8 million

Art prankster Banksy has struck again.

A work by the elusive street artist self-destructed in front of startled auction-goers on Friday, moments after being sold for $1.8 million (£1.04 million).

The spray-painted canvas "Girl With Balloon" went under the hammer at Sotheby's in London, fetching more than three times its pre-sale estimate and equalling a record price for the artist.

Then, as an alarm sounded, it ran through a shredder embedded in the frame, emerging from the bottom in strips.

A post on Banksy's official Instagram account showed the moment — and the shocked reaction of those in the room — with the words "Going, going, gone..."

"It appears we just got Banksy-ed," said Alex Branczik, head of contemporary European art at Sotheby's.

The auction house said it was "in discussion about next steps" with the buyer.

"We have not experienced this situation in the past . where a painting spontaneously shredded, upon achieving a record for the artist," Branczik said.

"We are busily figuring out what this means in an auction context."

Banksy, who has never disclosed his full identity, began his career spray-painting buildings in Bristol, England, and has become one of the world's best-known artists.

His mischievous and often satirical images include two policemen kissing, armed riot police with yellow smiley faces and a chimpanzee with a sign bearing the words "Laugh now, but one day I'll be in charge."

He has a penchant for elaborate pranks. In 2005, he hung an image of a spear-toting ancient human pushing a shopping cart in the British Museum, where it remained for several days before being discovered.

The next year he smuggled a life-sized figure of a Guantanamo Bay detainee into Disneyland.

"Girl With Balloon," which depicts a small child reaching up toward a heart-shaped red balloon, was originally stencilled on a wall in east London and has been endlessly reproduced, becoming one of Banksy's best-known images.