Nightmare Fuel / Metal Walker

  • The overworld as a whole. It's nearly deserted, for one. The people that are around are safe inside buildings, because the Metal Busters would attack if they went out.
    • The overworld also contains many destroyed buildings, and there is only one spot in the entire game with trees and grass.
  • The final boss of the game, the HEX System. It's an evil supercomputer that's behind everything bad, and it summons a powerful B. Knight to attack you.