I don't own Harry Potter. I just find it amusing when I mess about with things. This is just a simple one-shot. I think I'll be using this Moody in the Harry Black story, when I get back to it.
Harry shuddered. That clicking sound he'd grown to fear over the first few days of 5th year echoed down the halls. He, like many of the other students headed to the Great Hall for lunch, dove to one side of the hall, throwing up a shielding charm around himself and a few first and second years near him. The clicking grew raised his wand, prepared for the worst. Three Slythrin 4th years darted down the hall, ignoring Harry and the other students lining the walls. Harry held his breath, placing his finger to his lips as he signaled silence from the younger students beside him. They nodded, their own wands raised.
"CONSTANT VIGILANCE.'' A deeps voiced boomed. Six red lights flashed down the hall after the Slythrins. Harry blocked one with a quickly placed shield charm, another taken out by a 7th year with a banishing spell. Three bounced off the wall harmlessly, but the last found it's mark. One of the four fleeing slythrins fell. The clicking grew louder.
5th year was supposed to be his easy year. The year Harry really got down to studying, so he could get as many owls as he could. Harry wasn't stupid, or even lazy. But when a crazy dark lord decides that you need to die, school work tends to take a back seat to the nefarious plots against your life. Voldemort may have waited until nearly the end of the year, but the various other adventures around the castle were more than enough to keep him from making proper grades. When Harry had found out that Alastor Moody was once again taking up the defense against the dark arts position, Harry had been ecstatic. A proper teacher who wasn't bent on killing him. At last, Harry could learn something about defending himself from the maniac trying to end his life. Or, that's what he'd hoped for. But those long months in a trunk were not kind to old Mad Eye, and the elderly Auror spent several months in St Mungos. He'd lost his other leg, and more than a little of his fleeting sanity.
More red lights, two more finding their way into the backs of terrified Slythrins. Harry watched the hall while an older girl rushed to the Slythrins' aid, reviving them the best she could. A bright blue wave hit her in the back before Harry could stop it, sending her bouncing away. Harry signaled for the Slythrins to run. They made an honest effort, but the clicking had caught up to them.
Harry wondered who's idea it was, giving a man with so little mental stability the ability to walk on walls. Alastor Moody stood on the ceiling of the hallway, flinging curses and hexes at the misfortunate slyrthrins. From the waist up, Moody was normal old Moody, magical whirling around to catch any who tried to flee. Waist down was a different story. After loosing his other leg, Moddy had thrown a fit. Legless and immobile, Moody felt that he was an easy target. A sitting squirrel he'd said, much to the amusement of the muggleborn attendings. So the healers of St. Mungo's devised a plan. Something extreme, something bold, something creative. Something to get that mad man to shut up. The best Goblin smiths in the world devoted weeks to the device. But what had been a simple, two legged design, turned into the bane of every student in HOgwarts. The goblins in question had been unsatisfied by the boring wizard blueprint, and had made a few…changes. Perhaps if they'd been told who the prosthesis was for, they wouldn't have "improved" it as much as they had. But no one said a word, and the goblins made their changes. Mooody was thrilled. From the moment he'd sat in the contraption, he'd been in heaven. Six legged, wall climbing heaven.
Alastor Moody was a fearful image, and the fuel of many arachnid based nightmares. From his waist to his shiny metal toes, moody was more than five and a half feet of goblin steel and intricate clockwork. Six long, spider like legs gripped any surface he chose to stand on, the clockwork gears clicking away. He'd taken Albus up on his offer to continue teaching, far too enthusiastic about chasing children about on his ridiculously fast spider chair of doom. From his vantage point on the ceiling, Moody easily overwhelmed the students along the hall, Harry being the last one standing due to his intimate experience handling poor situations. But even he was felled eventually, the last thing echoing in his mind being a crazed voice shouting about vigilance before he finally went unconscious.
Albus Dumbledore pondered the hospital wing full of students. Madame Pomfrey was in a tizzy about the sheer numbers she had seen in the few short weeks of the school year. All at the hands of one Alastor Moody. Albus sighed. His dear old friend may have finally slipped a gasket, but the defense scores at the end of the year were almost assured. Albus sighed again. The things he ignored for the Greater Good.