S4, E12: Lana and Jason are attacked and almost killed by an unseen assailant, and recent psychiatric patient Alicia (recurring guest star SARAH CARTER) seems to be the prime suspect. Clark initially defends his new girlfriend, but when the evidence begins to pile up, he is forced to take a hard, truthful look at Alicia. Hurt by Clark's actions, Alicia forces Clark to unknowingly reveal his powers in front of Chloe. Meanwhile, Jason's mother, Genevieve (recurring guest star JANE SEYMOUR), returns to town with an offer for Lex.