From the Super Mario Wiki, the Mario encyclopedia
The Barfatronic Lavachomper is a large head that controls the flow of lava; it can be found solely in the game Wario: Master of Disguise at Sweatmore Peak. Wario has to fight the monster in order to pass.
First, Wario must become Captain Wario and fire torpedoes at three pillars at the bottom. While Wario is doing this, the Barfatronic Lavachomper's eye will open up and fire little balls of energy. After, a hand will come from its mouth and pull a switch, dropping bombs similar to Count Cannoli's. He needs to become Genius Wario and send one of the bombs flying at the Barfatronic Lavachomper's eye using the punching glove. This will hurt the monster and make it release a toilet from its mouth. Wario then must become Arty Wario and draw a dung (a mess-up) above the pipe. The dung will run and hit the Barfatronic Lavachomper's uvula. This will make a heart-like device come out. Using Thief Wario, tackle the heart until it breaks, causing the boss damage. It will then refill the arena with lava and the three pillars will respawn. Repeat the process two more times and the boss will explode and a scene will occur.
After the Barfatronic Lavachomper is defeated, the player will advance to the Blowhole Castle.
A device built to regulate the flow of magma, and also seek out and terrorize the occasional intruder. Why it is so darn weird is anyone's guess.
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