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A Decompressor is a piece of machinery in the Game Boy Advance game Wario Land 4. It only appears in The Curious Factory level, found in the Ruby Passage. It is a machine that reverses the effects of a Compressor. The Compressor crushes Wario when he walks under it, transforming him into Flat Wario. The effect can be reversed by entering a Decompressor, which will decompress Wario's body, turning him back to his normal self.
The Decompressor is a silver-grey color and appears to be made out of metal. It is cube shaped with two openings, one at the front and one at the back, for Wario to pass through. Two floor-level windows are on the front so that the player can see Wario getting recompressed. Yellow lights flash above the two openings and the windows. Wario in his normal form and even enemies can pass through a Decompressor without any effect. Besides from passing through a Decompressor, Flat Wario can also change back into his normal form by touching water.