It's time, he thought. Oh, yes, I've got him now.
The short little guy was bent over, washing his face, obviously secure enough to have removed that white mask. The Boo smirked to himself. Here I come, kid.
He moved down from his perch by a high window, moving down toward his part-time friend quietly, careful not to laugh. His menacing smile steadily grew wider, decorated by dull, white fangs. As he came near the young boy he shifted so his transparent shadow would not fall into his victim's vision, and as he came within several feet of his prey, he let out a loud cackle. The young Shy Guy knocked over the bucket of water and spun to face the round, chubby ghost. He stumbled away, embarassed, his hood falling off.
"Huh, wha?" The green-shelled Koopa opened a sleepy eye and glanced up and down the hallway he was supposed to be patrolling. What in the very name of King Koopa was that ungodly sound? He waited. After a few more seconds, the high, raspy shriek ceased.
"Those ghosts must be playing tricks on the kids again," said another voice. The sleepy Koopa looked up to see one of the older red-shelled Troopas wander up the hall. "Poor things. They're so dumb, and embarassed." He rolled his eyes, remembering when the younger Boos tried to scare a group of Troopas he was a part of. How fun that was. "Fools."
A quick, timid looking little Shy Guy came waddling up the hall, adjusting his red hood. The next day, none of the Boos could find the little troublemaker who'd gone out haunting the night before.
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Author's Note: If you did read this, then please, please review. This is, honestly, the first fanfiction I've ever written that seems to have any remote possibility of being very good at all - so I appreciate any feedback if you have the time.