A gamemode you can choose when creating a character. 2 seconds after you spawn in, scourge heads and the scourge wall will spawn making it difficult to collect items.
Note from ILIKETOEATPi: Build I suggest is to use the Bandicoot, Overworld Helm, and Haste Beetle. The best way to get damage out on the scourge wall in the last fight is to mine all the crystal fragments.
Tip from darkver: I beat it using- Scourgeling-Bat wing hat and - Gorgon Eye. You simply jump through all levels trying to collect potions and spam zombie staff.