Despite the Kool-Aid Man and his "Oh yeah!" catchphrase, you know the sugary drink has negative connotations if you've ever heard someone say, "Don't drink the Kool-Aid." That expression derives from a November 1978 murder-suicide involving hundreds of members of the Peoples Temple, as Mental Floss reports, a notorious story of one of the world's deadliest cults.

The man responsible for the Jonestown tragedy is Jim Jones, a former Methodist student pastor who founded the Peoples Temple movement in Indiana during the 1950s. Though it had the guise of a church at the time, Peoples Temple was actually Jim's version a Marxist commune. Soon, however, Jim stopped preaching Marxism and started warning his followers about a nuclear apocalypse that would devastate the world on July 15, 1967. He set up a safe haven for her devotees in in Redwood Valley, CA, but — surprise, surprise — that date came and went without any such doomsday.

By 1977, Jim had become concerned about the Peoples Temple's tax-exempt status and paranoid about the U.S. intelligence community, so he relocated his movement to his settlement in the South American country of Guyana, a camp he called Jonestown. In 1978, Congressman Leo Ryan visited Jonestown with a media delegation, in order to investigate allegations of human rights abuses at Jonestown. During his visit, more than a dozen Jonestown residents asked for his help defecting from the community. And when the congressman and his party tried to leave Jonestown on Nov. 18, 1978, Jim's men shot and killed him, as well as three members of the media and one defector.

Just after those murders, Jim called all the Jonestown residents together for a "White Night" meeting and ordered his acolytes to mix a deadly cocktail that included cyanide, diazepam, promethazine, chloral hydrate, and fruity drink powder. Jim had already prepped his followers for "revolutionary suicide" — which was, in his mind, an act of political protest. During those prior rehearsals, the followers didn't know the drink they were consuming wasn't poisoned. This time, however, it was.

Some of the other temple members suggested alternatives to suicide, but Jim's mind was decided. He told his followers the authorities would soon come to Jonestown now that the congressman was dead. Some people drank the poison by choice, and others were forced, as survivors later said. In total, more than 900 people died, including more than 300 children. Jim himself died from a gunshot wound that may have been self-inflicted.

So now when you hear mention of someone "drinking the Kool-Aid," you know that person is blindly following someone else's persuasion… And you also know the morbid backstory behind the expression. But here's the kicker: Apparently, most of the powder used was Flavor Aid, a Kool-Aid competitor. Evidence shows Kool-Aid was used, too, but that's the brand that got the bad rap!

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