One theory regarding Superman's vulnerability to kryptonite makes his infamous Achilles' heel much more dark. An iconic villain suggests there's more to the Man of Steel's greatest weakness than mere radiation.

There are several versions of kryptonite, each with its own deadly twist. But whether they mutate Superman, rob him of his powers, or simply cause him pain, the radioactive space rocks make Clark's life a living hell. Of course, due to their irradiated nature, kryptonite is also dangerous to humans. But for Superman, the presence of kryptonite is a matter of life and death.

Kryptonite Harms Superman Because it Channels the Screams of Krypton

In Adventures of Superman #32 by Jim Krueger and Neil Edwards, a Green Lantern has come to Earth desperate for Superman to kill him. This Green Lantern reveals that Krypton was once under his jurisdiction, and his guilt from failing to save the planet has been eating the Corps member alive. Superman, naturally, refuses to harm the Green Lantern, causing him to lash out with violence. The two get into a fight which ends with the Lantern's Power Battery exploding, accidentally exposing Superman to a piece of kryptonite. A hooded figure (later revealed to be Brainiac) appears and gloats at the incident. Brainiac theorizes that it isn't radiation that is harming Superman, but sound waves. The villain suggests that the screams of Krypton's people are imbued within kryptonite and that Superman is being tormented by their anguished cries.

It seems dubious that kryptonite causes Superman pain via sound waves rather than radiation. But there is a kind of logic to the theory. After all, Superman has been exposed to radiation numerous times from nuclear bombs but kryptonite is the only thing that exudes radiation that manages to bring Clark to death's door. While it's just a theory that Brainiac posits, it would explain why kryptonite weakens Superman so much compared to other radioactive sources. It also puts a dark spin on the hero's weakness, as it would mean Superman experiences the death of his home planet every time he encounters the glowing green rocks.

Superman Relives Krypton's Death with Kryptonite Exposure

If Brainiac is correct and kryptonite does channel the screams of millions of Kryptonians, then Superman is reliving the greatest tragedy in his life every time a villain exploits his weakness. What makes things worse is that Clark has no memory of Krypton's explosion since he was just an infant at the time. Whenever Lex Luthor or Metallo shines the sickly green glow of kryptonite upon the Last Son of Krypton, Clark becomes highly aware of the disaster he was too young to . If this theory holds water, then kryptonite isn't just Superman's greatest weakness, it's the worst torture for him imaginable.