When did clowns—the characters who filled our childhoods with juggling and balloons—become so creepy? For centuries, clowns have worn two faces: as irreverent entertainers, and tricksters who could break social norms. So when stories of scary clowns pop up all over popular culture, it's a sign that we're wondering who clowns really are behind the costume. Do they want to make us laugh? Or scream?