 Kali Rocha (qv), who showed up in the sixth season as vengeance  demon Halfreck, first appeared in a flashback episode in the fifth  season as Cecily, the woman who spurned William, causing him to  become the vampire known as Spike. Having already cast Rocha as  Halfreck, the writers knew the loyal fans would immediately  recognize her, so as an inside joke between them, when Halfreck  first saw Spike, she said, "William?"