This refers to the sourtoe drink which has a mummified toe.
Fron the Guardian article:
"For more than 40 years the Downtown hotel in Dawson City has served up the sourtoe cocktail, a shot of whisky with a blackened toe – nail and all – bobbing inside. Those who manage to touch the gnarled, severed toe to their lips earn a certificate.
On Saturday a customer took it one step further, allegedly making off with the wrinkled digit after swallowing his drink. “We are furious,” said Terry Lee of the hotel. “Toes are very hard to come by.”"