Moody swept the dead spider off the desk onto the floor.
“Not nice,” he said calmly. “Not pleasant. And there’s no countercurse. There’s no blocking it. Only one known person has ever survived it, and he’s sitting right in front of me.”
Harry felt his face redden as Moody’s eyes (both of them) looked into his own. He could feel everyone else looking around at him too. Harry stared at the blank blackboard as though fascinated by it, but not really seeing it at all…
So that was how his parents had died… exactly like that spider. Had they been unblemished and unmarked too? Had they simply seen the flash of green light and heard the rush of speeding death, before life was wiped from their bodies?
Harry had been picturing his parents’ deaths over and over again for three years now, ever since he’d found out they had been murdered, ever since he’d found out what had happened that night: Wormtail had betrayed his parents’ whereabouts to Voldemort, who had come to find them at their cottage. How Voldemort had killed Harry’s father first. How James Potter had tried to hold him off, while he shouted at his wife to take Harry and run… Voldemort had advanced on Lily Potter, told her to move aside so that he could kill Harry… how she had begged him to kill her instead, refused to stop shielding her son… and so Voldemort had murdered her too, before turning his wand on Harry.
Harry knew these details because he had heard his parents’ voices when he had fought the Dementors last year—for that was the terrible power of the Dementors: to force their victims to relive the worst memories of their lives, and drown, powerless, in their own despair.