Wasn't season 5 clif hanger Zod?
Season 6, Episode 1 – Aired: 9/28/2006
Zod
A powerless Clark is trapped in the "Phantom Zone" surrounded by the criminals his father imprisoned there. However, an unexpected ally comes to his aid. Meanwhile, Zod in Lex's body advances his plan to transform Earth into a new Krypton, while using Lana to produce an heir.