In the episode "Gingerbread", the town goes on a demon-induced, anti-witchcraft spree.
To escape being burned at the stake, Amy uses a transformation spell to turn herself into a rat.
Unfortunately, once she is in rat form, she cannot recite the spell to transform back (although some sources, for example 'The Buffy Monster Book', report that Amy's actual intention was to turn the townsfolk into rats and the spell ended up backfiring).
Willow captures her and keeps her in a cage while she researches how to turn her back into a human being.
Only Buffy and Oz are aware that Willow's new pet is a transformed human, with Willow referring to her as "Amy-Rat." When Buffy and Willow go off to UC-Sunndyale, Amy-Rat goes with them.
As a result of Willow's will becoming a magic medium through which any wish of hers instantly comes true in the Season Four episode "Something Blue", Amy is very briefly turned back into a human—and moments later, back into a rat.
Had the character of Amy appeared it would have marked her fifth appearance in the series, and the first time that the character would have appeared in more than one episode per season.She is not seen again in the TV series after this but no mention is ever made of her death, and it is presumed she most likely survived the destruction of Sunnydale by leaving beforehand along with the rest of the town's population.The character has appeared in the comic book series Buffy the Vampire Slayer Season Eight and Season Ten.As a result, Willow cuts Amy out of her life entirely.
Amy makes a final television appearance in the Season Seven episode "The Killer in Me" in which she again bewitches Willow, this time to cause her to appear as (and ultimately start to become) Warren Mears.Afterwards, Amanda moves into the Summers' residence, where she trains and becomes friends with her fellow Potentials.