LONDON (AP) — 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 1.04 million pounds ($1.4 million). In an Instagram post Saturday, Banksy claimed the dramatic artistic payoff had been years in the making.

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 equaling a record price for the artist.

Then, as an alarm sounded, it ran through a shredder embedded in the frame, leaving half th...