It all started with a marketing ploy to sell Smirnoff vodka, ginger beer, and copper mugs. Back in the 1940s, the three retailers couldn't move their products so they invented a cocktail that utilized all of them. The Smirnoff Mule became quite popular in the 50s and 60s, and then got a resurgence in 1996 when it was reintroduced in a copper bottle. The copper mug became the iconic container for this cocktail since the cold metal keeps the cocktail well insulated and cold.