It's the Auction House Ball, which went live in version 7.25.
The Auction House Ball is a festival that lasts for one day, on this day the auction houses in Ogle and Stormwind will be transformed into dance floors and temporarily lose the function of auctions, players enter the dance floor will automatically start to bop, in addition to the players on the dance floor there is a certain chance that they will be teleported directly to the main stage to dedicate a dance.
Players who enter the dance floor will be rewarded with a buff that lasts for 3 days, and their characters will automatically dance while standing still, in addition to regaining 5% of their life and mana every second if you are in a dancing state.
Expanded Information
Classic activities of Warcraft
1, Darkmoon Circus
Darkmoon Circus is an entertainment gathering organized by a dwarf, Silas Darkmoon, but the main purpose of Darkmoon Circus is to publicize the peace of the world, as well as to help the various races of the world sufferings. The Darkmoon Circus gives off a rare air of peace and friendliness, where even hostile humans, undead, orcs, jackals, ogres, and the like all come together as coworkers.
The Darkmoon Circus appears on the first Sunday of every month in the southwest of Thundercliff in Bullhead or in Shining Gold in Elvenwood in Humanity, and is held for a week.
2. Midsummer Flame Festival
People light bonfires in all the major main towns and Flame Festival camps around the world to symbolize that the hottest season of the year has arrived. Firekeepers look after the bonfires, ensuring that these bonfires are kept burning day and night during the festival.
The job of caretaker is not an easy one, and they are in desperate need of capable adventurers to lend a hand. Players will have to follow their orders, traveling long distances across the world and into dangerous dungeons. After completing their tasks, perhaps they'll be hot and sweaty, or even pudgy? But these fire protectors are quite understanding, and they'll reward adventurers quite handsomely.