https://www.gamespot.com/articles/fortnites-new-disco-domination-limited-time-mode-n/1100-6462422/

A new update is now live for Fortnite. Epic has rolled out Patch 6.02 across PS4, Xbox One, PC, Nintendo Switch, and mobile, bringing not only a new item to Battle Royale, but another limited-time mode to participate in: the recently teased Disco Domination. [Update: Epic has rolled out a hotfix for Disco Domination mode. Among other things, the patch increases the score requirement teams need to meet to win and decreases the rate at which the storm circle closes.]

As its name suggests--you can see it in the gameplay video above--Disco Domination is all about dancing. Players are divided up into two teams of 32, with the object being to dance on the various dance floors scattered around the island. Epic says five of these will appear when the storm isn't moving; when you come upon one, you'll need to first eliminate other players in the area, then emote on the dance floor to raise a disco ball.