A procedurally generated maze, haunted by XDLifeXD.
The portal into Void Rooms spawns at midnight on Day 6 of the Corruption Level 3 countdown. Time freezes the moment it appears, and only resumes once the player has left the dimension.
Inside is a procedurally generated, infinite corridor maze, five NBT structure pieces combined per chunk to build it. XDLifeXD haunts the maze: getting within 8 blocks sets it chasing with a glitchy, flickering sideways and back-and-forth movement, and closing to within 1.9 blocks is an instant kill.