Catherine Madison (aka Catherine the Great):
Debut -- The Witch (Season 1)
"Vanished" Same Episode
Catherine Madison, taking the form of her daughter Amy, is set on making the cheerleading squad. In order to better her chances, she casts spells on her competition. These include setting Amber on fire, disorienting and blinding Cordelia, removing one other girl's mouth while in science lab, and finally casting a spell on Buffy that should kill her. Apparently, Catherine can't deal with being an adult, can't stand to put on weight, and is basically shrewish. After Giles reverses all the spells, Catherine's back in her own body, and tries to send Buffy to "a dark place." But Buffy thwarts her when she kicks down a mirror -- because Catherine is now looking at herself in the mirror, she's now the victim of the spell. She vanishes from the room in a cloud of swirling lights. The gang's unaware of her whereabouts, but we see that she's now entrapped inside the cheerleading trophy she won for the school years ago. Her eyes are moving...
In a great continuity move on the writers' part, the trophy's eyes are featured in Phases, (Season 2), when Oz is seen staring at the trophy. He tells Willow he likes the trophy because it's like its eyes follow you.
Catherine's Most Unmotherly Line:
"You little brat!" -- to daughter Amy, about how she gave up her life so Amy could drag her "worthless carcass around and call it living."
ABCs of Sunnydale