Harold Dingle was a student at Hogwarts during the 1990s. He tried to sell a substance that he claimed was powdered dragon claw to students studying for their O.W.L.s. In truth, the substance was dried Doxy droppings, which Hermione Granger confiscated as a school Prefect. Harold later offered to sell Firewhiskey to Dean Thomas and Seamus Finnigan.