Red kryptonite inflicts bizarre and unpredictable - albeit temporary and nonfatal - symptoms, as when it divides Superman into twins or transforms him into an infant or a giant ant.
Red Kryptonite: Created from green kryptonite that passed through a mysterious red-hued cloud en route to Earth. Red kryptonite inflicts random effects on Kryptonians, typically creating an initial "tingling effect" in those affected. No two chunks of red kryptonite have the same effect. Red kryptonite effects typically last for 24-48 hours (though sometimes as long as 72), after which the Kryptonian in question is always immune to that specific chunk of red kryptonite. Superman has suffered the following effects upon exposure to various pieces of red kryptonite: being turned into a dragon, a non-powered giant, a dwarf, an ant-headed humanoid, a lunatic, and an amnesiac; being made unable to see anything colored green; growing incredibly long hair, nails, and beard; being rendered totally powerless; gaining the ability to read thoughts; losing his invulnerability along the left side of his body; being split into an evil Superman and a good Clark Kent; being rendered unable to speak or write anything but Kryptonese, the language used on Krypton; growing an extra set of arms; becoming clumsy when trying to help out; swapping bodies with the person nearest him upon exposure to it; rapidly aging; and multiple personality changes. In post-Crisis continuity, red kryptonite first appeared as an artificial construct of Mr. Mxyzptlk; a second variety was later revealed as a synthetic variant created by Ra's al Ghul, using notes he stole from Batman. The red kryptonite that Batman created is similar to the red kryptonite in the Lois & Clark series in which red kryptonite causes Supeman's powers to become uncontrollable.
Officially, each specific chunk of red kryptonite has the same effect on all Kryptonians. However, in one Superboy adventure from the mid-1950s, Superboy and his Kryptonian dog Krypto were simultaneously exposed to the same chunk of red kryptonite, with different results. Superboy (as himself, and in his Clark Kent identity) experienced an uncontrollable urge to eat any green objects he encountered, while Krypto experienced an equally uncontrollable urge to eat red objects. Superboy discovered the discrepancy when Krypto attempted to eat a red traffic light: when the light suddenly changed to green, Krypto lost interest but Superboy felt an overpowering urge to devour it.
