The Invention Of Kryptonite: The Real Reason The Man Of Steel Needed A Weakness
There are a few things that everyone knows about Superman: He's faster than a speeding bullet, he can leap tall buildings in a single bound, and his only weakness is Kryptonite. The glowing green rock—remnants of the crust of his home planet, Krypton—has no effect on humans but renders Superman completely powerless. This weakness hasn't always been a part of Superman's legacy; in fact, Kryptonite didn't even originally appear in the comic books. Still, it's become entrenched in the character's mythology.
Born From A Bathroom Break
Superman's first appearance was on the cover of Action Comics #1 in 1938, and the character's overnight popularity quickly earned him his own radio serial. The Adventures of Superman, which ran from 1940–1951 and comprised more than 2,000 episodes, was often recorded live, giving star Bud Collyer precious few opportunities to leave the booth when nature or otherwise pressing concerns called. To give the guy a break, the producers came up with the concept of Kryptonite. In such a weakened state, they reasoned, Superman's voice would naturally change, allowing another actor to step in while Collyer took care of business.