Though keen to acknowledge the power of art to inspire and influence in profound ways, critics and creators continue to deny there is any link between art and the real world violence it sometimes begets. But after this summer's shootings at a cinema in Colorado, and a spate of other copycat crimes by Joker-wannabes, perhaps it's time we confronted movies that turn psychopathic characters and their acts of violence into stylish spectacles.

Incidences at an international music festival. Moments that are now dead forever.