Fiery mechanical steeds are best when they can be used with friends. Coming Soon™. pic.twitter.com/M8ulGgD105- World of Warcraft (@Warcraft) April 25, 2014
Moments ago, the official Warcraft Twitter account teased a new mount. As can be seen in the tweet above, the phrasing includes "best when they can be used with friends." That may imply it's part of a Recruit-a-Friend relaunch, though speculation reserves the possibility that it may simply appear on the Blizzard store.