The Fortnite island flipped over during Chapter 2’s final event

Fortnite’s big chapter-ending event just ended, and it was a big one. After an all-out war against UFOs, zombies, and the Cube Queen, players were saved in a rescue mission led by Dwayne Johnson. (Well, his in-game character.) Then, the island flipped over.
The event

Let’s back up a bit. The game’s latest season has been all about the cubes, and right when the event loaded up, a mysterious giant blue cube spawned on the map next to all of the players in my lobby. Jumping at the cube bounced players away, but it otherwise, didn’t do anything beyond loom ominously. We also could look at the Cube Queen in the distance, which has been floating in an energy ball over the center of the island for part of the season.