I figured this would be something fun to roll into the weekend with! The Reins of the Golden King is a new Bind on Account Alliance-only ground mount obtained through the new guild system. Once your guild has completed the Dungeon Diplomat guild achievement, you can purchase the mount with gold.
The white areas on the mount will be where your guild crest displays, so don't worry and think it's bugged because of that. It looks so much better in the game than it does in screenshots and model viewers. -worldofraids