Amy is a classmate of Buffy's at Sunnydale High School. She first appears in the season one episode, "Witch", when she and Buffy both try out for cheerleading. Amy performs poorly in the tryouts, but a series of strange injuries to other contestants move her up in the standings. Buffy suspects that Amy is a witch who is using her powers to harm the other girls so that she can be a cheerleader. Investigation reveals that Catherine, Amy's mother and a very powerful witch, has switched bodies with her because she wants to relive her youth. Buffy and the Scoobies succeed in restoring Amy to her own body and (unknown to them) trapping her mother in an old cheerleading trophy.
Amy's next notable appearance comes in season two's "Bewitched, Bothered and Bewildered" where Xander realises that she has inherited her mother's powers, becoming a potent, if sometimes ineffective, witch, and blackmails her into casting a love spell for him. Although it was intended to make Cordelia fall in love with him, the spell backfired instead, causing every woman in Sunnydale to fall for him - including Amy. In a jealous rage, she invoked the Goddess Hecate to turn Buffy into a rat. She is eventually forced by Rupert Giles to undo both of her spells.
In the season three episode "Gingerbread" Amy, along with Willow and Buffy, are the focus of the witch hunt that sweeps Sunnydale, and are nearly burned at the stake. Amy escapes by transforming herself into a rat, which becomes a problem because no one was able to turn her back. She lives as a rat for the next few seasons, cared for by Willow.Amy appears for just a moment in Season Four's "Something Blue", elated when Willow's "let my will be done" spell allows Willow to unknowingly change her back into a human, then dismayed when Willow just as unknowingly changes her back into a rat.
By Season Six, Willow has become an extremely powerful witch and permanently "de-rats" Amy by simply conjuring up an incantation. The two become friends again, though Amy now seems to be drastically different than she was before, possibly due to her long experience of being a rat. She had apparently been involved with the warlock Rack before being transformed, and gets Willow involved as well, leading Willow to become addicted to black magic. Later, when Willow decides to give up magic, Amy casts a spell on her, causing her to magically manipulate everything she touches for a while. Willow complains to Amy that this makes her attempts to give up magic even harder. Amy responds by mocking her, implying that she did it as revenge for being trapped as a rat for years. As a result, Willow cuts Amy out of her life entirely and makes it clear to her that she is no longer welcome in the Summers household.
Having transformed aesthetically into Warren Mears, whom she tortured and flayed in a rage over the murder of her girlfriend Tara Maclay, Willow seeks help from the UC Sunnydale Wicca Group and discovers that Amy is a member. Amy explains that she had hit "rock bottom", and was doing much better now. It is soon revealed that Amy is in fact responsible for Willow's transformation, the result of a hex placed on her apparently out of jealousy and spite. However, in Season Eight, it is revealed that this seemingly random event is actually part of a larger plan orchestrated by Warren, after Amy rescued him from death in the earlier episode "Villains."
Amy is discovered by the United States Army during an expedition to be living sixty feet under the Hellmouth after its collapse with her "boyfriend," an unrevealed creature whom General Voll regards with disgust. Her first words to an exploratory member were, "I'm gonna help you kill her." In exchange for their cooperation, Amy requests unlimited access to all the government's magical hardware as well as a weapons lab for her "boyfriend". If they succeed in taking Buffy down, Amy wants full immunity and release for the both of them.
Amy attacks Buffy at the Slayer's base in Scotland, putting her under a mystical sleep which only a kiss of true love can undo. Raising an army of kilted zombies to battle the Slayers, Amy battles Willow mid-air before being stepped-on by Buffy's now-giant sister Dawn Summers. As Willow magically probes Amy's whereabouts, she suddenly senses a trap and is pulled through a portal, only to be "greeted" by a saw-wielding and skinless Warren. As Warren tortures Willow, Amy faces off against Satsu and an awakened Buffy, who manages to channel enough of Willow's magic to defeat a demon which Amy conjured. Having seen her dreamspace while asleep, Buffy takes the form of Amy's worst nightmare: her mother. Distracted, Amy fails to notice a grenade thrown at her feet by Satsu, and as Buffy and Satsu charge into the room containing Willow, they see Amy appear and teleport away with Warren in her arms.
Later, in "Time of Your Life", she and Warren are shown working under direct orders from Twilight, under whom General Voll served. Together they have constructed a missile, covered in mystical runes and candles, and targeted it at the Scottish citadel where the Slayers reside. Some time after, Warren and Amy argue over the failed attack on the Castle (with Warren threatening to make a robot Amy "with no mouth").
Powers and abilities
Amy is a powerful witch with abilities inherited from her mother. These powers grow throughout the series. While initially more powerful than Willow, casting a spell to become a rat that Willow cannot initially reverse, Amy acknowledges in Season Seven that Willow has surpassed her. Willow comments that Amy's new found power in Season Eight (which she claims has grown since the events of "Chosen") has been technologically augmented to some degree, with Amy commenting that she has grown consistently stronger stranded in the ruins of Sunnydale. In battle, Amy is able to stand up against Willow and fly by force of will.
- Xander Harris - After a spell Amy casts which was supposed to make Cordelia love Xander goes wrong, she, along with every other woman in Sunnydale, falls in love with Xander ("Bewitched, Bothered and Bewildered"). This attraction ends after Rupert Giles gets Amy to reverse the spell.
- Larry Blaisdell - Amy stated that she thought Larry was considering asking her to the prom, apparently unaware he was gay and the fact that the graduation of her class occurred three years before, when Larry died.
- Warren Mears - Amy's skinless boyfriend in Season Eight. It is revealed in "The Long Way Home" that the two had been in a relationship since "Villains", where after Warren was flayed alive by Willow, Amy saved his life. Amy refers to Warren as "sweetie", while he claims that "her magic is my skin." Amy constantly refers to Warren as her boyfriend as well.
- Elizabeth Anne Allen appears at least once in every season of Buffy except Season Five.
- Although initially starting off as a seemingly good natured individual, Amy gradually grows to misuse magic throughout her appearances on the show, eventually ending up following in her mother's footsteps and even surpassing her.
- After being turned into a rat, Amy-Rat is shown at random times through out the rest of Season Three as well as seasons Four, Five, and Six before finally being changed back.
- Amy as a rat was in the room in her cage in during "Graduation Day, Part 1" when Willow loses her virginity.