In "Buffy", Oz is a taciturn, guitar-playing teen who becomes Willow (Alyson Hannigan) 's boyfriend. After first appearing in the episode "Inca Mummy Girl", Oz discovers he is a werewolf in the episode "Phases" and becomes a recurring character throughout the second season. Green is elevated to main cast for the third season, and departs from the series in season four. Green portrays the character for a final time in the season four finale "Restless" as part of a dream sequence. The character made a brief canonical 'return', however, in the 2002 "Buffy the Vampire Slayer Season Eight" storyline "Retreat".