Demon Head is the final boss of the game Virtual Boy Wario Land, encountered in Stage 14. Aside from a few images of his head in certain rooms of the game, he isn't seen or mentioned before facing him in Stage 14. In the game's manual, an emblem of his head is seen as a background image on pages 28-31 where the enemies are described, although he is not directly mentioned.
Demon Head is a large, gruesome creature with wide eyes, pointy ears and a curl on top of his head. The end of his large nose partially covers a gaping mouth with six visible fangs. Further down is the neck against a ribcage, and a genie-like wisp on the tail end. Demon Head possesses two large, detached hands, each with three claws. His pupils will stay focused on Wario during the battle.
Most of Demon Head's attacks involve the use of his two hands; often, he will slam his claws down onto the stage, likely hitting Wario. This attack is typically used after Demon Head has been damaged. A similar attack involves Demon Head leaving his hands suspended just above the stage, moving each one in turn above where Wario is standing, and slamming them onto the stage. He is also able to rapidly swipe both of his hands across the stage without warning, harming Wario if he doesn't jump in time to avoid the attack. As the battle progresses, Demon Head's attacks will become faster.
Periodically during the battle, Demon Head will spit out a line of flames which will split off into two, and will quickly move along the ground towards the edges of the stage. These flames can be avoided by jumping. This attack is always consecutively executed three times in a row, unless Demon Head is harmed while the attacks are being performed.
After defeating the guard of Stage 14, it will turn into a Jump Transporter, giving Wario access to the Boss Door which will open as he approaches. Wario will land in the area where the final battle will take place. This area is a dark stage, with a round platform situated in the foreground. This platform has an image of the Demon Head, viewed in angled perspective in the center. This platform acts as a large Jump Transporter, which Wario can use to jump back and forth between a similar platform in the background of the stage. On either side of the platform are pulsing waves of light which serve as a background effect. Soon after Wario enters the stage, a portal will appear between the circular platforms and the Demon Head will be seen emerging from it. Its eyes will look from side to side before it approaches Wario in the foreground. After his hands and body appear, Demon Head's eyes will focus on Wario, and the battle will begin. While moving, Demon Head will flicker rapidly, with motion blur giving the impression that his body is transparent during gameplay. However, his claws will become solid when they move into the foreground to attack Wario. The Demon Head's nose is the only part of him which remains solid throughout the entire duration of the battle.
The nose is Demon Head's weak spot; if Wario hits it while he uses the platform to travel between the foreground to the background, Demon Head will scream and retract in pain as his pupils will spin rapidly. He will then quickly rise into the air and out of sight, and come plummeting down a few seconds later, slamming his claws into the stage. Throughout the battle, Demon Head will keep moving at different heights, so the player won't always have the chance to hit his nose. Periodically during the battle, Demon Head will turn invisible for a short time. During this phase, if Wario is to try moving between the foreground and to the background, or vice-versa, he might bump Demon Head while he is invisible. Likewise, there is a chance that Wario might hit Demon Head's nose while he is invisible. If Wario is defeated, Demon Head will laugh maniacally.
After Demon Head has been damaged three times, he will begin "bouncing", instead of slowly moving around the stage. This makes it more difficult for Wario to damage him again. One of his claw attacks will also become more complicated, with both of his hands able to criss-cross over each other.
Striking Demon Head's nose five times will defeat him. He will freeze for a few seconds, then his clawed hands will fall off and fall straight down, his body will disintegrate, and his face will then begin to rapidly spin around, getting smaller and smaller, finally disappearing. Wario will then fall through the floor, landing at the treasure cave seen at the beginning of the game. Depending on how well Wario progressed in the game, the cut-scene which follows will vary. The credits will roll as Wario makes his way home.