Superman #243 (1971)

THE STARRY-EYED SIREN OF SPACE! A female alien intelligence creates a body for herself, and is endangered by menaces of her own subconscious creation. Her mate asks Superman to help save her, and then, when she falls for Superman, builds a duplicate Superman body for himself, and attacks him. Eventually, the misunderstanding is cleared and Superman is able to return to Earth via the Timestream. THE DEATH-TRAIL OF KRYPTON! 2000 years ago, a Kryptonian chemo-engineer named Dol-Nd discovered that he could create flying wings for himself by using a crystalline element he named Trolium, after Trolius, the mythological lord of Krypton's red skies. However, the Trolium created permanent green death-trails in the sky after his flight, which disintegrated any object that flew into them. After defeating a criminal who tried to steal the wings, Dol-Nd destroyed his invention, but the death-trails remained in the sky until Krypton's destruction. THE BATTLE OF THE ATOMS! This story is reprinted from Superman #38.