Kryptonite

Kryptonite is a trans-uranium element (atomic number #137) suspended in a tellurium-silica crystal lattice. It is an extremely rare element naturally occurring only in a few places in the universe. Notably it was present in the solar system of the planet Krypton.

Kryptonite absorbs and gradually re-admits trapped gamma radiation. These energetic discharges are not wholly benign but brief exposure is generally harmless to most sapient life forms. Kryptonians are extremely sensitive to the emissions of Kryptonite. The circulatory system absorb the particles into the bloodstream and the body's mitochondria are drained of the energies that fuel a Kryptonian. Ten minutes of exposure is usually fatal; recovery takes approximately ten minutes per minute of exposure to regain full capacity. Kherans have a weaker reaction to Kryptonite but even brief exposure acts as a carcinogenic substance.