The Coca-Cola Company used to mix a new batch of their famous secret cola formula only once every two years, highly concentrated in a series of giant vats at their main production facility outside Atlanta, Georgia. This practice was discontinued in 1968 after the Carl Jackson incident.
Carl was a factory technician employed at the facility, who went missing in April of 1966, around the time of the mixing ceremony. Carl's case vexed detectives and police officers for nearly two years, until technicians preparing for the next mixing were shocked to find Carl's ID badge along with the remains of his uniform and a few telltale lumps of calcium stuck to the bottom of one of the spent storage vats.
Although most of the batch that made it to market was immediately recalled and donated to the family of the deceased, a few bottles of the brew, dubbed "Coca-Carl" by rare-soda collectors and enthusiasts, can occasionally be spotted at auctions for exorbitant prices. Interestingly, batches of Coca-Cola made with the formula from Carl's vat performed markedly better in taste tests against competitors over those two years.