Ep 12 Labyrinth

Clark (Tom Welling) is attacked and wakes up in a mental asylum where the attending physician, Dr. Hudson (guest star Matthew Walker), tells him he has been there for five years due to his elaborate fantasy that he has alien superpowers. In this new world, Martha (Annette O'Toole) is married to Lionel Luthor (John Glover), Chloe (Allison Mack) is deemed insane and Lana (Kristin Kreuk) chose Clark over Lex (Michael Rosenbaum).

Lana begs Clark to agree to Dr. Hudson's treatments so they can be together, but when a fellow patient named John, A.K.A Martian Manhunter (guest star Phil Morris), tells him the good doctor is actually a phantom and he needs to kill him in order to return to reality, Clark must make the toughest decision of his life.