Superman’s one weakness has become so well know in popular vernacular, one might go as far as to say kryptonite is synonymous for Achilles heal. Kryptonite was invented in 1943 for the Superman radio program so Superman’s voice actor could rest. It was incorporated into the comics in 1949. The most common form of kryptonite is green, which is generally deadly to the man of steel. Other versions include red, which generally makes Superman loose his inhibitions, blue which poisons bizzaros, and gold which renders kryptonians mortal. However these powers are never consistent.
Its one thing for kryptonite to change effect on Superman from appearance to appearance, but within the one episode it changes function. Smallville is the worst offender. Green poisons and weakens him. Red intoxicates him. Black creates two entities out of one being. Blue kryptonite is shown to render Clark powerless and cause bizzaros to overload. Kryptonite or in the earlier seasons “green meteor rocks” cause a wide spectrum of mutations in people. A recent episode had different types of kryptonite taking away and restoring Clark’s powers as the plot demanded. Sometimes he can use his powers when being poisoned, other times he can barely stand.
Superman Returns is a close runner up. Lex Luthor created an island made of kryptonite. Superman lands and doesn’t realize he’s standing on a mountain of poison. It weakens him so much that three human thugs can beat him up. Lex shanks him with a shard of kryptonite and kicks him in the water. When Lois Lane finds him she removes the shard, and Superman is able to throw the kryptonite island into space. How was he strong enough to do that when he’d just been stabbed in the side and it’d been show that he was completely mortal at this point? Doesn’t green kryptonite poison and kill him anyway? Wouldn’t he have noticed from a distance that it was hurting him as he flew to the island?
As a fictional material with ridiculous effects, kryptonite needs specific rules to follow in order to be believable. These rules cannot be broken as the plot requires. I would make them the following:
- Green kryptonite slowly poisons Superman causing him great pain. He can still have his powers but it causes him such agony, that its harder to use them.
- Superman should never be rendered completely helpless by exposure. His strength of will would push him to keep going.
- Even a little bit of kryptonite would be noticeable to Superman.
- The only effect kryptonite would have on humans would be cancer after very long term exposure.
- In a movie keep the colors of kryptonite to a minimum. If any variation appears it should only be red.
- Red Kryptonite should only hurt Superman mentally, having the effect of making him lose his inhibitions, or act evil.
- If an enemy like Metallo is powered by kryptonite, Superman should be able to battle him. Over the course of the fight, his powers would be shown to slowly fail, because it would cause too much pain.
- Sunlight would speed Superman’s recovery from kryptonite exposure.