〃Er；〃 said Ron tentatively； 〃my dad told me about one。。。 Is it called the Imperius Curse； or something？〃
〃Ah； yes；〃 said Moody appreciatively。 〃Your father would know that one。 Gave the Ministry a lot of trouble at one time； the Imperius Curse。〃
Moody got heavily to his mismatched feet； opened his desk drawer； and took out a glass jar。 Three large black spiders were scuttling around inside it。 Harry felt Ron recoil slightly next to him…Ron hated spiders。
Moody reached into the jar； caught one of the spiders； and held it in the palm of his hand so that they could all see it。 He then pointed his wand at it and muttered； 〃Imperio！〃
The spider leapt from Moody's hand on a fine thread of silk and began to swing backward and forward as though on a trapeze。 It stretched out its legs rigidly； then did a back flip； breaking the thread and landing on the desk； where it began to cartwheel in circles。 Moody jerked his wand； and the spider rose onto two of its hind legs and went into what was unmistakably a tap dance。
Everyone was laughing…everyone except Moody。
〃Think it's funny； do you？〃 he growled。 〃You'd like it； would you； if I did it to you？〃
The laughter died away almost instantly。
〃Total control；〃 said Moody quietly as the spider balled itself up and began to roll over and over。 〃I could make it jump out of the window； drown itself； throw itself down one of your throats。。。〃
Ron gave an involuntary shudder。
〃Years back； there were a lot of witches and wizards being controlled by the Imperius Curse；〃 said Moody； and Harry knew he was talking about the days in which Voldemort had been all…powerful。 〃Some job for the Ministry； trying to sort out who was being forced to act； and who was acting of their own free will。
〃The Imperius Curse can be fought； and I'll be teaching you how； but it takes real strength of character； and not everyone's got it。 Better avoid being hit with it if you can。 CONSTANT VIGILANCE！〃 he barked； and everyone jumped。
Moody picked up the somersaulting spider and threw it back into the jar。
〃Anyone else know one？ Another illegal curse？〃
Hermione's hand flew into the air again and so； to Harry's slight surprise； did Neville's。 The only class in which Neville usually volunteered information was Herbology which was easily his best subject。 Neville looked surprised at his own daring。
〃Yes？〃 said Moody； his magical eye rolling right over to fix on Neville。
〃There's one…the Cruciatus Curse；〃 said Neville in a small but distinct voice。
Moody was looking very intently at Neville； this time with both eyes。
〃Your name's Longbottom？〃 he said； his magical eye swooping down to check the register again。
Neville nodded nervously； but Moody made no further inquiries。 Turning back to the class at large； he reached into the jar for the next spider and placed it upon the desktop； where it remained motionless； apparently too scared to move。
〃The Cruciatus Curse；〃 said Moody。 〃Needs to be a bit bigger for you to get the idea；〃 he said； pointing his wand at the spider。 〃Engorgio！〃
The spider swelled。 It was now larger than a tarantula。 Abandoning all pretense； Ron pushed his chair backward； as far away from Moody's desk as possible。
Moody raised his wand again； pointed it at the spider； and muttered； 〃Crucio！〃
At once； the spider's legs bent in upon its body； it rolled over and began to twitch horribly； rocking from side to side。 No sound came from it； but Harry was sure that if it could have given voice； it would have been screaming。 Moody did not remove his wand； and the spider started to shudder and jerk more violently…〃Stop it！〃 Hermione said shrilly。〃
Harry looked around at her。 She was looking； not at the spider； but at Neville； and Harry； following her gaze； saw that Neville's hands were clenched upon the desk in front of him； his knuckles white； his eyes wide and horrified。
Moody raised his wand。 The spider's legs relaxed； but it continued to twitch。
〃Reducio；〃 Moody muttered； and the spider shrank back to its proper size。 He put it back into the jar。
〃Pain；〃 said Moody softly。 〃You don't need thumbscrews or knives to torture someone if you can perform the Cruciatus Curse。。。 That one was very popular once too。
〃Right。。。 anyone know any others？〃
Harry looked around。 From the looks on everyone's faces； he guessed they were all wondering what was going to happen to the last spider。 Hermione's hand shook slightly as； for the third time； she raised it into the air。
〃Yes？〃 said Moody； looking at her。
〃Avada Kedavra；〃 Hermione whispered。
Several people looked uneasily around at her； including Ron。
〃Ah；〃 said Moody； another slight smile twisting his lopsided mouth。 〃Yes； the last and worst。 Avada Kedavra。。。 the Killing Curse。〃
He put his hand into the glass jar； and almost as though it knew what was ing； the third spider scuttled frantically around the bottom of the jar； trying to evade Moody's fingers； but he trapped it； and placed it upon the desktop。 It started to scuttle frantically across the wooden surface。
Moody raised his wand； and Harry felt a sudden thrill of foreboding。
〃Avada Kedavra！〃 Moody roared。
There was a flash of blinding green light and a rushing sound； as though a vast； invisible something was soaring through the air…instantaneously the spider rolled over onto its back； unmarked； but unmistakably dead。 Several of the students stifled cries； Ron had thrown himself backward and almost toppled off his seat as the spider skidded toward him。
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 e 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。
Moody was speaking again； from a great distance； it seemed to Harry。 With a massive effort； he pulled himself back to the present and listened to what Moody was saying。
〃Avada Kedavra's a curse that needs a powerful bit of magic behind it…you could all get your wands out now and point them at me and say the words； and I doubt I'd get so much as a nosebleed。 But that doesn't matter。 I'm not here to teach you how to do it。
〃Now； if there's no countercurse； why am I showing you？ Because you've got to know。 You've got to appreciate what the worst is。 You don't want to find yourself in a situation where you're facing it。 CONSTANT VIGILANCE！〃 he roared； and the whole class jumped again。
〃Now。。。 those three curses…Avada Kedavra； Imperius； and Cruciatus…are known as the Unforgivable Curses。 The use of any one of them on a fellow human being is enough to earn a life sentence in Azkaban。 That's what you're up against。 That's what I've got to teach you to fight。 You need preparing。 Y