From: Nocturnes by John Connolly, Atria Books, 2006.
This story follows William, a ten-year-old boy fascinated by the circus. When the Circus Caliban comes to town, William is given a ticket to its one-night-only performance. That night, he wanders away from his parents, curious that he hasn't seen any clowns.
Finding his way into a secluded tent, he discovers the clowns are disguised as people. When they rub off their flesh-colored makeup their true features are revealed, including orange hair, whiteface, and prickly tongues. They speak a language William doesn't understand at first, but eventually he learns not only that clowns hate and kidnap children, but that he is a clown himself.
What sounds far-fetched to describe is made believable by the atmosphere and tone Connolly establishes. If you aren't afraid of clowns, you may well be after reading this story.