Onyx

Plot:

An experiment with heated (black)kryptonite at Luthorcop causes an explosion which badly wounds Dr. Sinclair, the scientist in charge, and creates a molecular copy of Lex which has the evil side of his personality. While the real Lex shows Clark the experiment was to create far stronger crops, the evil one gives Sinclair a fatal injection in hospital after questioning him. Fearing an effect on himself, 'Evil Lex' locks the good Lex up wearing an iron mask and sets out ruining lives in Smallville, such as closing the Talon when Lana refuses to be his girlfriend, and taunting Lionel Luthor badly enough to make him turn away from charity. When Chloe shows Clark proof on hospital video recordings there must by two Lex's, super-boy is duped into telling the fiend everything, believing him to be the real one, so the Clark family and Chloe become his prime targets, and he knows about green kryptonite and it's affect on Clark.