Smallville - Season 4 - Eps 17: Onyx
A black kryptonite explosion splits Lex in two and his evil side - Alexander - is released. Alexander imprisons Lex in the mansion then gives full vent to his evil side - he threatens to evict Lana from the Talon unless she becomes his mate, jousts with Lionel, and tries to kill Clark and Chloe when they figure out his secret.
About Smallville

Title: Smallville
First Air Date: 2001-10-16
Last Air Date: 2011-05-13
Status: Ended
Rating: 8.2/10 (from 4151 votes)
Language: EN
Seasons: 11
Total Episodes: 216
Network: The WB The CW
Genres: Sci-Fi & Fantasy, Action & Adventure, Drama
Production Companies: DC, Warner Bros. Television, Tollin/Robbins Productions, Millar Gough Ink
Synopsis
The origins of the world’s greatest hero–from Krypton refugee Kal-el’s arrival on Earth through his tumultuous teen years to Clark Kent’s final steps toward embracing his destiny as the Man of Steel.
Cast

Tom Welling
Clark Kent

Erica Durance
Lois Lane

Cassidy Freeman
Tess Mercer

Justin Hartley
Oliver Queen