Mad Eye' Moody on the Avada Kedavra curse: "Not nice," he said calmly. "Not pleasant. And there's no counter curse. There's no blocking it. Only one known person has ever survived it, and he's sitting right in front of me.
J.K. Rowling, Harry Potter and the Goblet of Fire
avada-kedavra, curse, death, harry-potter, mad-eye-moody, survive