https://www.pcgamer.com/fortnites-halloween-event-is-live-glider-redeployment-added/

Fortnite's Halloween event—the aptly named Fortnitemares—rolls out today, as part of its update v6.20. Likewise, new Playground items have been added, the new Six Shooter pistol fires into action, and glider redeployment enters all game modes. 

Teased above, Fortnitemares sees The Cube spawning Cube Monsters. Large Cube Fragments are now scattered in corrupted areas of the map. Small Cube Fragments generate randomly during matches. And Cube Fiends, Brutes and Fragments can all drop loot.