Green kryptonite

Green Kryptonite is a fictional mineral featured in comic book titles published by DC Comics. It relates to the Superman family of comics as well as its various spin-off and adaptation media. Kryptonite was actually first featured in the 1940 Adventures of Superman radio series, but has since been included in the comics themselves, and has appeared in nearly every iteration of the franchise. Kryptonite possesses different properties depending upon its color. The most common form of Kryptonite is Green Kryptonite, which weakens a Kryptonian who is exposed to it, ultimately killing them.