Black Kryptonite is a form of Kryptonite ussually reffered to as Black K.
Effects on HumansEdit
Black Kryptonite can split a person into the good and bad half and fuse them together on second time exposure.
Effects on KryptoniansEdit
The effect on Kryptonians is much more drastic.The Kryptonite splits the Kryptonian into a human and Kryptonian persona while both have their abilities.