A glimpse of the future Lex Luthor is revealed after a Kryptonite explosion splits Lex in two, and his evil side -- Alexander -- is released. Alexander immediately imprisons Lex in the mansion and begins his rampage by attempting to kill Clark and Chloe in the lab, jousting with Lionel and convincing him to return to the dark side and, finally, threatening to close The Talon unless Lana moves in with him.

Season 4 | Episode 17

Allison Mack

Chloe Sullivan

Annette O'Toole

Martha Kent

Erica Durance

Lois Lane

John Schneider

Jonathan Kent

Kristin Kreuk

Lana Lang

Michael Rosenbaum

Lex Luthor

Tom Welling

Clark Kent