There's no word on how the shredder started operating at the key moment after the auction, though it could have been activated by a remote mechanism.
The painting, which was sold to an undisclosed buyer, passed through a concealed shredder within the picture frame as soon as the sale was finalized at an auction at Sotheby's in London.
Was Banksy in the room during the auction?
In this undated photo provided by Sotheby's the spray-painted canvas "Girl with Balloon" by artist Banksy is pictured.
Banksy is known for his stunts.
Banksy - whose identity still has yet to be confirmed - often incorporates political messaging, anti-capitalist ideas, and art world satire into his work.
The auction house told the Financial Times: "We have talked with the successful purchaser who was surprised by the story".
Banksy works including Slave Labour are due to go under the hammer and auctioneers have promised no items will "shred or explode".
"We are busy figuring out what this means in an auction context ..."
Suddenly, Banksy works were fetching tens of thousands of pounds at renowned auction houses and the mysterious street artist was world famous. Art experts are now saying the half-destroyed work could be worth up to double as much as intact copies. Millions of people have seen Banksy's video of the stunt on Instagram, and it captured worldwide headlines over the weekend.
Orange County-based artist Jeff Gillette, whose 2010 "Dismayland" works portraying a slum surrounding the theme park were included in Banksy's similarly titled project, calls Banksy's newest prank 'brilliant'.
Internet sleuths located another image of the incident, showing a man with a camera phone videoing it. "It's certainly the first piece to be spontaneously shredded as an auction ends".