Since 1978, people have been terrified of Michael Meyers in the Halloween films, but very few people know of the real-life encounter that inspired the character. 

The original film’s director and co-writer John Carpenter revealed that a creepy encounter he had while attending Western Kentucky University served as inspiration for the fictional serial killer.

“I had a class — psychology or something — and we visited a mental institution,” he said in the documentary A Cut Above the Rest. “We visited the most serious, mentally ill patients. And there was this kid, he must have been 12 or 13 and he literally had this look.”

The look, Carpenter said, is best described by the lines he gave to Donald Pleasence, who played Michael’s psychiatrist Dr. Sam Loomis in Halloween and four of its sequels: “This blank, pale emotionless face. Blackest eyes. The devil’s eyes. I spent eight years trying to reach him and then another seven trying to keep him locked up, because I realized what was living behind that boys’ eyes was purely and simply evil.”

“It was unsettling to me, it was like the creepiest thing I’d ever seen as a stranger,” John reflected. “It was completely insane.”