AN: Thanks for all your amazing reviews. I hope you like this one. Now remember, pranks are a recurring theme in this story so this isn't the first one based on a prank but it also won't be the last. Enjoy.

Morgan was still fuming over the last prank Reid had pulled on him. That screaming recording gave him a headache plus it took him hours to find it and get it off his iPod. It had been added as an encrypted file and Garcia had refused to help him. Reid thought he had won the battle but Morgan was determined to win the war and since Reid decided that making as much noise as possible and issuing headaches was the way to win, Morgan was going to fight fire with fire. And he already knew how he was going to do it. Reid better watch his back, Morgan was ready to beat him once and for all. Insert internal evil laugh.

A few days later, Reid hurried into the bullpen, the Metro had been running late this morning and he hadn't wanted to get in any trouble for being late. Luckily the only other person in the bullpen was Emily. Both Hotch and Rossi were up in their offices and hadn't noticed his late arrival. Emily gave him a knowing smile as he gratefully sat on his chair.

Only to leap off it again as a loud burst of noise came from his chair. Emily also jumped at the noise and her hand instinctively went for her gun before Reid pushed down on his chair again and the same noise came from it.

"What was that?" Emily asked as Reid looked at the bottom of his chair and found an air horn taped just underneath the seat. Reid detached it and held it up before turning to Emily.

"Was this you?" Reid asked and Emily shook her head.

"Would I have reacted the way I did if it was?" Emily countered and the noise caused by the air horn hadn't gone unnoticed as both Hotch and Rossi emerged from their offices at the noise.

"What is going on?" Hotch asked looking at the two agents as Reid finally worked out what had happened. Oh it was on!

"Someone and I think I know who put an air horn under my chair." Reid explained, his brilliant mind already plotting revenge. Sweet, sweet revenge.

"Get rid of it and get back to work then." Hotch replied and Rossi gave Reid a knowing grin; he knew Morgan wasn't going to let that last prank slide but he was all for letting the two agents have their fun.

Reid tossed the air horn into a trash bin and sat back at his desk and began working through the pile of paperwork on his desk. Not long afterwards however, his need for caffeine made itself known and Reid walked over to the kitchen area to make himself coffee. When he saw the sugar jar was empty, he innocently went fetched sugar from the cupboard it was kept in and almost had a heart attack as another air horn which was hidden inside the cupboard was triggered as he shut the door again. This time Emily laughed and as if on cue, Morgan emerged from his office, a wicked grin on his face as Reid tried to get his heart rate under control again.

"What's the matter Reid, you look like you've seen a ghost." Morgan commented as he got himself coffee. Again Reid tossed the air horn into the bin and glared at Morgan.

"I will destroy you." Reid vowed as JJ entered with another case file. After a quick briefing, they passed the case and basic profile onto the B team and went back to work. This time Morgan and JJ loitered in the bullpen, JJ to get some coffee and have a quick gossip with Emily and Morgan to show off just how evilly he had planned this little prank. All throughout the briefing, Reid had been nervous and jumpy, hardly daring to even sit at the table or say anything. This was hilarious.

"Hey Reid you wouldn't have a stapler I could borrow could you?" Morgan asked innocently, ignoring the suspicious look Reid gave him as he opened his desk drawer, handed Morgan the stapler and carefully pushed the drawer shut again, expecting yet another air horn to go off in his face. Reid turned to hand the stapler to Morgan, who quick as a flash pulled a third air horn out from where he had hidden it in the hem of his jeans and hidden by his shirt and let a loud blast from the horn off in Reid's face.

Reid fell to the floor in shock and JJ shouted loudly and looked as though she was about to do something but Emily, sensing blood, grabbed her arm and shook her head. This was between the boys. They would be smarter to stay out of it. Sure enough Reid got up and before anyone could say or do anything, with some previously unknown or hidden strength, Reid tackled Morgan and began throwing punches at him. Morgan was initially too shocked to react before instinct took over and he began blocking the shots. Hotch and Rossi who had heard yet another air horn blast quickly ran down from their offices and pulled Reid off Morgan.

"What the hell is going today?" Hotch demanded, giving both Reid and Morgan a Level Two glare that had them feeling more than a little scared.

"He put air horns everywhere and been tormenting me all day." Reid insisted.

"Hey he started it. I was only getting back at him for what he did to me!" Morgan claimed.

"Alright that's it. Your prank war has gotten way out of hand and gone way too far. The next one of you who pranks the other is going to be suspended from work for a month. No arguments. Also if anyone brings one of these into the BAU again, they're suspended." Hotch ordered as he and Rossi let Reid go. Morgan tossed the air horn into the trash and the rest of the day was passed with neither agent saying another word to each other.

Reid was contemplating the risks involved in one last retaliatory prank against Morgan when he considered Hotch's warning and hit a brainwave. Reid hurried to find Morgan and explain his plan. Maybe it was time to put aside their differences and unite their pranking skills into an alliance wherein they didn't prank each other but instead they pranked together. But as they came up with a plan, the first thing Reid was insistent be ruled out were air horns. Aside from that, anything and everything was fair game.

After all, Hotch had said Morgan and Reid weren't to prank each other…

Rule 35: Air Horns are banned from the BAUHot