The WB's Official Description: "Oracle"
CLARK IS VISITED BY JONATHANS GHOST Clark (Tom Welling) is stunned when he sees his fathers ghost (John Schneider) at the graveyard, but becomes even more confused after Jonathan tells him he must kill Lionel (John Glover). Meanwhile, Lex (Michael Rosenbaum) develops a vaccine for Fines (guest star James Marsters) deadly virus, but Fine intervenes and injects him with the vaccine, which causes a shocking reaction in Lex. Kristin Kreuk, Erica Durance, Allison Mack and Annette OToole also star.. The episode was written by Caroline Dries and directed by Whitney Ransick .
TVGuide's Official description for "Oracle"
Suspicions about Lionel Luthor's intentions are raised when Clark and Martha receive ghostly visits from Jonathan, who tells them that Lionel must die. Meanwhile, Lex's trust in Milton Fine is taxed when Fine demands the vaccine.