A Hogwarts ghost; she was a student who died in a bathroom because she saw a basilisk while Tom Riddle (later Voldemort) was at school. She spends most of her time in the bathroom where she died, though she does imply to Harry that she spies on male students in the Prefects' bathroom. When Harry uses the Prefects' bathroom to prepare for the second task, Myrtle shares what Cedric did to figure out the egg and guides Harry in interpreting the egg's riddle.