Does Your Wolpertinger Linger? is related to the seasonal event Brewfest. Completing this achievement is also an objective of the meta achievement .
On US servers, you can complete the quest or to satisfy this achievement. On EU servers during the 2009 festival the quest has been removed, but the can be bought from Belbi Quikswitch (Alliance) or Blix Fixwidget (Horde) for 50s.