Diablo's 20th Anniversary was a one-time mini holiday event which ran from January 5 - 9, 2017. During the event, a number of toys and other novelties were obtainable in World of Warcraft, which were references to the Diablo franchise. The Cow King could be looted once a day per character and was guaranteed to drop a [Twelve-String Guitar] toy, and potentially a [Horadric Satchel], [Livestock Lochaber Axe], or other holiday items.