A Christmas Story is this year's inspiration for WoW's yearly present.
This year Blizzard's present under the great tree is the Red Rider Air Rifle. It's a usable item that comes with 200 charges and can be used to "Pelt" the enemy. For this year's achievement, which isn't required for the meta, you will need to pelt all of the enemy leaders.
Happy Holidays everyone!
Related World of Warcraft News :