Buffy the Vampire Slayer

The Sadie Hawkins dance is approaching, but Buffy isn't in a romantic mood, and goes to the library to see if there's any slaying to be done. There she stops a boy from killing his girlfriend with a phantom gun. The next day, Xander is attacked by a disembodied arm in his locker, Giles sees another couple fight in exactly the same way as Buffy did — only this time the man shoots the woman — and the cafeteria is infested with snakes. The gang decides a poltergeist is to blame, and try to exorcise it, but the ghost brings on a horde of wasps. The ghost is that of a Sunnydale student who killed his lover, who was a teacher in the school, then killed himself out of guilt. Later, the ghost lures Buffy into the school, and Angelus goes to kill her; however, he becomes possessed by the teacher's personality, while Buffy becomes the boy. She shoots Angelus (which doesn't kill him, of course) and he forgives Buffy / the ghost, which finally allows the ghost peace. Meanwhile, Spike has secretly recovered from his spinal injury.