Harry's aunt. Though she's spent most of her life insisting that her son Dudley is big-boned and a gentle giant, this summer forces her to confront the truth: Dudley's school nurse insists that he needs to go on a diet to lose weight. To try to make Dudley feel better, Petunia insists that everyone in the house observe the diet as well. She's distraught when Dudley eats one of Fred's Ton-Tongue Toffees.