That was the question on everyone's lips when one of the Bristolian street artist's paintings mysteriously self-destructed as the auction drew to a close.
In a screengrab of a conversation with the artist, he said: "I don't charge people to see my art unless there's a fairground wheel", in reference to his dystopic amusement park Dismaland, which he opened to the public for a fee in Weston-super-mare in 2015.
The framed piece shows a girl reaching towards a heart-shaped balloon and was the final work sold at the auction.
Bidders looked shocked as the piece was torn to shred by a shredder built into the gold frame.
"We have not experienced this situation in the past.where a painting spontaneously shredded, upon achieving a [near-] record for the artist".
Posting a picture of the moment on Instagram, Banksy wrote: 'Going, going, gone'. "We are busily figuring out what this means in an auction context", he added.
Sotheby's said this was "certainly" the first time a work of art started to shred itself after coming under the hammer.
The move is the latest in a long history of anti-establishment statements by the street artist, who claims he does not make any money from his artworks.
Girl With Balloon originally appeared on a wall in Great Eastern Street, London.
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.