A police officer in uniform walked into 20 classrooms at El Camino High School in California and announced that several students had been killed in car wrecks over the weekend.
The hoax was intended to teach the dangers of drink-driving.
But the scare tactic backfired when some students, who were not told that it was a stunt for two hours, became hysterical and wept uncontrollably.
Their grief turned to fury when they learned they had been duped.
Some students made posters declaring: “Death is real. Don’t play with our emotions”, while a number of parents also complained to the education department.