Some examples of superhero weaknesses include Superman's weakness to Kryptonite, Green Lantern's weakness to the color yellow and Wonder Woman's weakness to her own magic lasso. Superheroes' weaknesses make them more complex characters and allow for conflict within stories.
As the archetypal superhero, Superman is nearly invulnerable except for his weakness to Kryptonite. An alien from the planet Krypton, Superman derives his powers from his presence on Earth. However, his superhuman abilities can be negated by radioactive fragments of his home planet, which render him as weak as any ordinary human.
Green Lantern takes his abilities from his powerful ring, which can create anything its wearer imagines. However, the ring's weakness to the color yellow makes it vulnerable to any number of ordinary items.
Wonder Woman's greatest strength is also one of her only weaknesses. Her powerful lasso can force anyone to tell the truth, but it is also the only item capable of binding Wonder Woman herself.
Like Wonder Woman, many of the X-Men possess abilities that are also weaknesses. Team leader Cyclops emits powerful optic blasts from his eyes, but the ability is so dangerous that it can be controlled only with a special ruby quartz visor. Teammate Rogue can drain the strength and abilities of those she touches, but this ability makes it impossible for her to touch friends or loved ones without hurting them.