The Pack
Original air date: April 7, 1997
While on a field trip at school, Xander and four bullies become possesed by a hyena and begin attacking people.
While being possesed by the hyena, Xander tries attack Willow and tells her he won't have to look at her "Pasty Face" anymore which devistates her, and he also attempt to rape Buffy, but she escapes. Also, the pack attack Principal Flutie and kill him when he tries to talk to them in his office. (Xander was not part of that killing)
Episode Highlight: When Buffy tells Giles that Xander has been acting strange: picking on the weak, change of clothes style, attitude change and hanging with imbeciles, Giles explains Xander has simply become a sixteen year old, then sarcastically adds that "Of course, you'll have to kill him."