Don't Ever Get Sick at Granny's (R.L. Stine's Ghosts of Fear Street, No 16)

Dad said", Don't ever get sick at Granny's". Now Corey knows why. After he's dropped off at Granny Marsha's for the weekend, his temperature skyrockets. And Granny goes into action. She's determined to destroy every last germ in Corey's body--even if it means destroying Corey!