WoWDB

This is a special ability that will appear after successfully dancing on the Will of the Emperor encounter in Mogu'shan Vaults.  You have three seconds to use the ability before your extraactionbar button with the ability disappears.  Tanks will have to get good at dancing and use this button after almost every dance, both because it is necessary for their survival but also because this is the primary way that the bosses are killed, as DPS are often handling adds.