The Witches of Worm

"The Witches of Worm" is a 1972 young adult novel by Zilpha Keatley Snyder, and received the Newbery Honor citation in 1973. In it a lonely pre-teen girl, the protagonist Jessica, finds a blind, almost hairless cat that she names Worm. A reclusive elderly neighbor helps her to raise it. Worm seems to have a terrible hold on Jessica, and it is suggested the cat possesses her to do mean and destructive things to her friends and her somewhat childish and emotionally-distant divorced mother. Jessica comes to believe Worm is being possessed by a group of witches that includes her elderly neighbor. Jessica’s destructive actions escalate until her mother attempts to send her counseling. Enraged by this idea, Jessica runs away.

It is left to the reader to decide if in fact anything actually supernatural is going on.

This book has a history of being banned from school libraries because of its focus on the subject of witchcraft, the description of visions/nightmares Jessica experiences, and its protagonist's disturbing inner monologues with Worm/herself.