In 1933, Hungarian pianist Rezső Seress composed a song titled Gloomy Sunday, but is now known as the Hungarian Suicide Song due to the reportedly high number of people who commit suicide while listening to it.
For nine months in 1898 two Tsavo lions hunted and killed men working on the railroad being built in across the Tsavo river. But what drove them to view humans as food? Lack of their normal prey, injuries, or just a taste for human blood?
In an incident suspiciously similar to the Ken McElroy episode--except that there was no bullying redneck, no pickup truck and no gunfire--hundreds of residents of Pont St. Esprit in France found themselves hallucinating wildly. 7 died and many were institutionalized, and speculation is that it could have been ergot poisoning... or a CIA plot.