Tess McAnn is the granddaughter of Jim McAnn one of the founders of the MidWestern Brewery Company, makers of Thighslapper Premium Ale.
Her uncles Trevor and Ray are killed by a Shōjō released by Dale Lampert. Her grieving mother Lillian pours an orange juice for Tess, and one with vodka for herself, which Tess accidentally drinks. Inebriated, Tess can see the Shojo as it kills her mother.
When Garth and Dean speak to her, she is initially reluctant to talk about what she saw. However Garth enlists the help of Mr. Fizzles, and Tess reveals that she did see "a monster with claws" after she had drunk her mother's alcohol.