Charlie is a friend of Donna Shoemaker.
When Donna Shoemaker utters the name "Bloody Mary" three times while in front of a mirror with her friend Charlie, Charlie seeks out the Winchester brothers for protection. She fears that Bloody Mary will kill her because her former boyfriend threatened to kill himself if she broke up with him. When she did inevitably leave, he committed suicide. Sam and Dean Winchester remove or cover all reflective surfaces in their motel room to hinder Bloody Mary's access to Charlie, where she waits while they destroy the creature. They succeed when Dean shows the ghost her own reflection in the mirror and smashes it, defeating her. Charlie thanks Sam and Dean before they drop her off at her house, and Sam tells her she should forgive herself about what happened to her boyfriend.