James Potter was not in a good mood, he was sitting in McGonagall's classroom quill in hand supposedly writing the lines 'I must not do potions homework in transfiguration', 1000 times. Instead he was staring wistfully out the window listening to the cheers and groans from the Slytherin – Hufflepuff game. A sharp rap came from the front of the room and James turned his head quickly in that direction, "Hurry up Potter. Neither of us wants to be here and the faster you get those lines done, the faster we can get to lunch." McGonagall reprimanded him. James looked down at his parchment, 'Well,' he thought, 'at least her detention has worked. I'm never going to do my homework in class again, and get caught..'. James continued with his lines hoping to see at least the end of the match.

Earlier

Sirius Black was in the bathroom attached to the 7th year dormitory, beside him Remus Lupin was consulting a book while looking at a potion bubbling in a cauldron.

"Well," Sirius asked, "how's it look?"

"I think that's about it." Remus replied, "It's too bad the book doesn't have a picture, only a description. Does it look like mud to you?"

"I suppose so. I can't see it getting anything more like mud." Sirius took the spoon that was sitting in the potion and dropped some of the thick liquid back in. "It's rather disgusting really, I hope it looks better with the hair."

Remus grimaced, "I'm glad that you're going to be the one to test it. I certainly don't want to have to swallow that." Both boys shared a disgusted look before turning back to the potion. "So, what's the plan? Who are you going to turn into and what are you going to do?" Remus asked Sirius, who was still contemplating the thought of drinking the fowl potion.

"Well I was thinking of playing a little prank on our dear Slytherin friends. The Quidditch game starts in an hour so a little mischief to their uniforms could be entertaining."

Remus chuckled, "So what, you'll go down as a Slytherin? You'll find it hard to get some hair before the team goes down to change."

"Nah, I'm going as James."

Remus looked shocked at this revelation, "Sirius, we've done some pretty dodgy things to each other but we've never gotten each other in trouble."

"That's the genius part Mooney, James won't get in trouble because he's already in trouble."

Remus looked confused at Sirius' logic and waited for him to elaborate.

"You see Mooney, Prongs left for detention with McGonagall half an hour ago, and he'll be there for most of the game. While he's there he can't possibly have tampered with the Slytherin robes as McGonagall's watching him. So if anyone sees me, they'll just get called a liar." Sirius leaned against the wall in a cocky manner as if he had just come up with the best plan in world. Remus nodded, "Seems a solid enough plan to me. But what are you actually going to do to the robes."

"That my friend is a surprise."

Half an hour later Sirius, as James, was sneaking around the sheds of the Quidditch pitch heading for the Slytherin change rooms. With a quick glance around to check no one was there, he slipped into the change room and shut the door behind him. As quickly as possible he opened all the lockers and cast a few charms on each of the robes inside, and just for good measure he also cast the charms on the spare robes hanging nearby. Satisfied with his work Sirius headed back to the door and opened it running straight into Severus Snape.

Snape sneered at Sirius, "Lost four-eyes?"

"Not at all Snivillus, but I think you may need some lessons on insults. Four-eyes is more of an 8 year olds go to name don't you think?"

Snape ignored the jibe and looked past him into the change room, "What were you doing in there? Tampering with the Quidditch balls? Madam Hooch would be interested to know you were poking around."

Sirius laughed at Snape, "Now, now Snivillus, be careful what you insinuate before you have proof. I was just looking for Madam Hooch, I wanted to book the pitch for Gryffindor practise next week but obviously she isn't here. Well, see you later Snivillus." Sirius began to walk away but turned and called back, "Also Snivillus, you'd best stay away from Lily, she says she's outgrown having someone watch her from the bushes."

Sirius chuckled as Snape stared at him in shock. 'Yep,' he thought, 'he'll definitely think I was James now.' Rather pleased with himself he set off back to the dormitory to wait for the potion to run out before he would head to the game.

The Slytherin – Hufflepuff game was going as everyone expected much to the disappointment of the Gryffindor, Ravenclaw and Hufflepuff students. Slytherin was up by 100 points and the Hufflepuff's seeker was already looking tired. Contrary to the obvious conclusion to the game, there had been a rather large turn-out as not many students would miss a Hogwarts Quidditch match. The game appeared to be winding down when a rather observant Ravenclaw first year pointed at the Slytherin keeper. It appeared that the air around him was shimmering and within a matter of minutes his robes disappeared to reveal only his underwear. The students from Slytherin gasped in shock a few barely managing to hold back snickers while the students of the other three houses roared with laughter. Just as the keeper and the other players on the field noticed what had happened the other Slytherin players robes also began to shimmer before disappearing leaving them also only in underwear.

Over in the Gryffindor stand Remus shared a subtle high-five with Sirius but whispered to him, "It's not over yet, you only get the credit if you don't get in trouble for it." The game quickly wound down as Madam Hooch called for a time-out and the professors quickly entered the pitch to figure out what was going on. A few of the students from other houses also descended to the pitch wanting to be the first to know what was happening. Sirius and Remus were among them.

Upon reaching the pitch they saw Snape elbowing his way towards Madam Hooch. The young flying instructor was irate trying to solve the mystery of the disappearing robes while Professor Dumbledore simply stood behind her fighting of chuckles. Snape waited till he stood directly in front of Madam Hooch and the Headmaster before he opened his mouth.

"Madam Hooch I know who did it." He said with an air of superiority.

"Well boy, out with it. Who was the culprit?"

Snape grinned glad he could get James into trouble, "It was James Potter. I saw him sneaking around the Slytherin change rooms not long before the game. I had a feeling he looked suspicious."

"Is that so Mr Snape?" a voice asked from behind him. Snape turned to see Professor McGonagall with James standing beside her.

"Yes Professor it is. I saw him not more than half an hour before the game."

Professor McGonagall did not look impressed. "Mr Snape, I know for a fact that you are lying. Mr Potter has been in detention with me since breakfast. We have only just come down to watch the end of the match."

Snape began spluttering at this news, "But Professor I know I saw him, it had to have been him because he said..." Snape cut off awkwardly not wanting to reveal his past with Lily in front of such a big crowd.

"That's enough Mr Snape, 20 points from Slytherin for lying and trying to incriminate an innocent student."

Snape spluttered again, "But, but Professor..."

"I said enough," she cut him off sharply, "if you insist on continuing this falsehood it will be detention."

"But Professor it was him."

"Detention Mr Snape, tomorrow night, after dinner."

Snape immediately stopped talking and hung his head, thinking to himself that he would get Potter back for setting him up because it had to have been him.

Later

In the Gryffindor common room Sirius related the entire story to James.

"So not only did you get away with an awesome prank, you also managed to get Snivillus into detention for lying about it." James said through laughter.

"Yep," Sirius replied, "you'll be hard pressed to beat that one Prongs."

James grinned, "Challenge Accepted."

Authors Note: Hey there readers. Wow it has been so long since I posted a story, or updated TOTWGA (and I am so sorry for that, please don't throw things at me). So this is another collaborative piece between myself and DiNozzofan, hopefully it will usher in my return to writing fanfiction.

Happy Reading, Faith.

p.s. I couldn't help but put in that little HIMYM reference, it's my new favorite t.v. show at the moment.