Wes Craven was inspired to write his 1984 horror hit "A Nightmare on Elm Street" after a real-life case of what was called Sudden Unexplained Death Syndrome that, according to several articles in the Los Angeles Times, was afflicting America's Hmong refugee population. People would suffer from horrifying nightmares and soon became afraid to fall asleep. When they did finally lose consciousness, they mysteriously died. The deaths remained unexplained for years. Craven extrapolated a horror movie from these cases, envisioning a nightmarish killer who occupied multiple people's dreams. If the killer killed you in your dream, you died in the waking world. 

Craven named his killer Freddy Krueger (Robert Englund) and explained that Freddy was the ghost of a neighborhood child murderer who had been killed by a group of local parents -- exercising vigilante justice -- years earlier. Somehow, Freddy passed into the realm of the supernatural. Now he "lives" as a burned-up,...