The World's Best Builder Mug is a Server Reward that is unlocked from achieving the obscure server rank. The Wooden Spoon of Obscurity was originally planned to be the obscure server reward before it was removed from the game. The world's best builder mug was also planned to be the reward for getting to Legendary status, but was replaced by the Engine Axe. It is the first server reward to unlock.
The World's best builder mug was released in Patch 1.09 on August 10, 2011 along with five other server rewards.