On April 1961, the dreaded city shrinking super villain Brainiac returns to Earth to steal aluminum, which is valuable on another strange world. Conversely, when the mighty man of steel, Superman arrives to stop him, Brainiac activates a powerful force field in order to protect himself from the man of tomorrow. He then unleashes the terrible radiation rays of a brand new form of the only substance that can harm Superman, Kryptonite, which this time is a combination of the deadly Green Kryptonite and the unpredictable Red Kryptonite called Red-Green Kryptonite! The actual Kryptonite itself is not seen and may perhaps only exist in a form of a ray.
This new form of Kryptonite causes Superman to grow an eerie third eye on the back of his cranium. Fearing that this new grotesque deformity could expose his secret identity to the world when he switches back to his secret identity of mild mannered reporter Clark Kent, Superman leads the general public to actually believe that the effects of Red-Green Kryptonite gave him the uncontrollable urge to wear different types of hats. When Brainiac finally returns, Superman uses his incredible powers of heat vision, which now, thanks to the addition of a third eye, has far more power than before and thus Superman is able to infiltrate Brainiacâ€™s force field and finally defeat the space traveling green-skined android (Act No.275, Apr 1961: "The Menace of Red and Green Kryptonite!").