The mischievous artist Banksy pulled off another practical joke. His painting Girl with Balloon sold for one million pounds at Sotheby’s auction house in London. Moments after the auctioneer yelled “Sold,” an alarm sounded and the painting slipped halfway through a shredder mounted inside the bottom of the frame. Banksy tweeted a picture of bidders gasping at his ruined masterpiece, with the caption, “Going, going, gone.”

Banksy relished pulling one over on the wealthy, but he need not have bothered. Wealth itself has plenty of pranks up its sleeve. God says, “Do not wear yourself out to get rich . . .…