BRISTOL, ENGLAND—Dropping his spray paint in annoyance and grabbing a length of extension cord, the anonymous street artist Banksy methodically killed another few kids Thursday after they stumbled upon him painting the side of a building. “Aw, Christ, not again,” said the famed muralist, who casually wrapped the cord around the neck of a stunned teenager after first knocking each of the friends unconscious with several blows from a steel pipe. “This is starting to get exhausting. Just once I’d like to finish a painting without interruption, but I’m always having to stop, kill two or three people who have spotted me, and then find a way to dispose of their bodies. It’s such a fucking nuisance.” At press time, a London art dealer confirmed an authorized Banksy work consisting of two teenagers’ cell phones covered in blood had sold at auction for 1.2 million pounds.