The Sourtoe Cocktail is practically a rite of passage for visitors to Dawson City, Yukon. It's a simple drink (a shot of whiskey, usually Yukon Jack) with an unusual accompaniment: a mummified human toe.

How did the Sourtoe cocktail come to be? It all started during probition, with a nasty case of frostbite.

In the 1920s, the rum-running Linken brothers — Louie and Otto — got caught in a blizzard. Louie put his foot through a patch of ice and soaked his foot. When the brothers got back to their cabin, Louie's right foot was frozen solid.

RELATED: Sourtoe: The Story of the Sorry Cannibal

To prevent gangrene, Otto used his axe to chop off Louie's toe. He placed the toe in a jar of alcohol to commemorate the event.

In 1973, legend has it that Captain Dick Stevenson found the jar (and the toe) in a remote cabin.

He came up with the idea of the Sourtoe Cocktail Club — an exclusive club, with one membership requirement.

In order to gain admittance to the club, potential members must drink the legendary sourtoe coctail. There's just one rule: "You can drink it fast. You can drink it slow. But your lips must touch that gnarly toe."

In 2013, one man swallowed the toe. On purpose. He was run out of town. But he came back, seeking forgiveness from the people of Dawson City. Watch Sourtoe: The Story of the Sorry Cannibal.