On Friday, auction house Sotheby’s sold a painting by British graffiti artist Banksy for $1.4 million. The piece was a copy of one of the artist’s most famous works, an image of a girl releasing a red balloon, and moments after it was sold, the painting self-destructed, shredding itself while onlookers watched.

In a video, Banksy explained that he had secretly installed a shredder in the frame of the painting, titled “Girl with Balloon,” to destroy it if it ever went up for auction. The anonymous artist is known for creating satirical and subversive political art, and by shredding the painting, he essentially turned the auction itself into a work of art, quoting artist Picasso in an Instagram post: “the urge to destroy is also a creative urge.”

Sotheby’s described the painting as a “framed work, spray paint and acrylic on canvas,” and notes that it’s “the first time in auction history that a work of art automatically shredded itself.” It’s certainly a long-simmering plot, and it seems unlikely that the shredder and its power source would have remained a secret for so long.

The painting itself was a 2006 reproduction of the iconic image, which features a girl releasing a red balloon. The original image was spray painted on a building in East London in 2002, although it was covered up for many years before it was removed in 2014 and sold at auction the following year. Other copies of the painting have been auctioned over the years.