Disclaimer: All characters property of JK Rowling

A/N: Beta'd by the ever so talented Good_Witch and written in response to TPP's Anything Goes challenge. Writing this was great fun, I hope you enjoy it!

Regulus was expecting a typical detention, not a visit to Dante's ninth circle of Hell. By typical detention he thought Professor Slughorn would set him some lines, then shoo him out after a half hour with a finger wag and an understanding 'boys will be boys' smile. Nothing that would deter him from cutting class again. Not tonight, however.

Of course, cutting class was only a small part of his misdeeds for the day, but as far as he knew, it was all Slughorn was aware of. The real truth was more childish and satisfying than Regulus cared to admit. And, it worked out so perfectly that even the minor slip of being caught out of class by McGonagall was trivial.

He and Warren Montague had spent a good week or so developing a time delayed love potion. One little sleight of hand on Montague's part that morning and three quarters of an hour later, Sirius would be falling madly in love with Slytherin's less-than-finest beauty, Hortensia Greengrass. And her boil.

Warren went on to History of Magic, which Regulus thought was stupid since Professor Binns wouldn't notice if they were there or not and this show was going to be too good to miss. The delay was not quite as long as he'd hoped, but it was enough to get Sirius from the Great Hall to Care of Magical Creatures which Gryffindor and Slytherin sixth years shared. Regulus was ready, stationed in the fourth floor corridor with the ominoculars his father had bought him at the last year's Quidditch World Cup. He was not disappointed.

Hortensia proved to be quite a runner as she tore across the grounds with Sirius in hot pursuit. Professor Kettleburn followed the best he could with his peg leg, as did Sirius' three friends and the rest of class. It was a brilliant show, one Regulus would never forget, especially since he could review it over and over again with the replay button on his ominoculars. The scene ended when Hortensia doubled back at the Whomping Willow, catching Sirius off guard and giving Potter a chance to tackle him.

All in all it was a perfect plan, until Professor McGonagall happened to step out of the staffroom while he was making his way to the library to hide. But, no matter, it was only a detention. With Slughorn, no less.

"I have a special task for you, Regulus m'boy. Just don't let the others know, they'll think I'm playing favorites." He followed up his statement with a sly wink. Regulus smirked to himself as he led him through the door to his private chambers. Slughorn was too easy sometimes. "You'll be helping me go through my wardrobe."

Regulus paused. That sounded… boring. Still better than lines or cleaning cauldrons. He followed him into the magically enhanced wardrobe. To say Slughorn was a clotheshorse was a bit of an understatement. The room was as big as his at Grimmauld Place and was packed to the gills with velvets, satins, leathers and silks. He looked to have more clothes than Bellatrix, Andromeda and Narcissa combined—a feat he did not think was humanly possible. Regulus shuddered when he noticed the pile next to him, even the man's unmentionables were velvet.

He was right about boring. Slughorn paraded by in outfit after outfit, all of which were at least a size too small. Regulus was running out of original comments. Pretty much every ensemble made him think 'You look like a giant velveteen walrus.' He knew better than to speak his mind though. His father taught him one must never speak their mind around women. In fact, better to never speak at all. Regulus was sure that rule applied to professors as well.

Just when he thought he had served his punishment tenfold, Slughorn's booming voice announced, "I haven't seen these in ages!" Regulus looked up from the thorough study of his fingernails he was engaged in to see him holding up some material in the most lurid green color he had ever experienced. Nature herself could not have produced such a hue.

"You know, I was quite the ladykiller when I was your age. The witches…" Regulus could not follow what he was saying for Slughorn had waved his wand and the gaudy material appeared on Slughorn's body in the form of tight fitting pants approximately five sizes too small. Regulus was frozen in terror. He wanted to look away, but was unable to in the same way one cannot look away from a Manticore attack. "…see they've got this spell on them, one little word and all the buttons release. I remember one girl, Agnes Cornpuddle. She had the most amazing…"

As he spoke, the buttons that ran down the sides of each trouser leg quivered. Regulus was sure that if he listened hard enough, he could hear their tiny voices screaming for mercy. In that moment, Regulus not only resolved to never play a prank on his brother again, but swore on Merlin's Wand that if he escaped from that closet with those poor pants intact, he would apologize to Hortensia. And he might even stop making fun of her boil.

"Are you all right, boy? You look pale." Slughorn took a step toward him, stretching the pants to the point where only the strongest of magicks could keep them from breaking away on their own. Okay, he would definitely stop making fun of her boil.

"I'm fine, sir." As long as those pants hold up.

"Well, good, so what do you think? Should I—oh look, a Galleon!"

"I'll get it, sir!" Regulus jumped to retrieve it before Slughorn could bend over and Regulus saw something no Obliviate could ever take away.

"Thanks, you're a good lad." Slughorn looked at him sharply as he spoke. He tried to keep a calm countenance, but the sweat on his brow and fear in his eye could not be masked. "I think you've had enough detention for one night. I trust you've learned your lesson." He patted Regulus' shoulder.

"I have, sir." With that, he left the wardrobe as fast as his feet would carry him to go apologize to Hortensia, and her boil, personally.

Horace Slughorn chuckled to himself. In an instant he magicked his original trousers back on and took a deep breath. Still smirking, he flipped the Galleon in the air and caught it deftly.

"Works every time."