Kryptonite, which robbed Superman of his powers, is no longer the stuff of comic books and films.
A mineral found by geologists in Serbia shares virtually the same chemical composition as the fictional kryptonite from outer space, used by the superhero's nemesis Lex Luther to weaken him in the film "Superman Returns."
"We will have to be careful with it — we wouldn't want to deprive Earth of its most famous superhero!," said Dr Chris Stanley, a mineralogist at London's Natural History Museum.
Laugh it up, scientist boy, but if Lex Luthor gets his hands on this it will be THE END OF SUPERMAN... FOREVER!