It was a normal day in Red's base. Pinkie had just set up a new teleporter. Big Mac was about to use it when Rainbow Dash pushed him out of the way, causing him to say, "Hey! Rainbow, you never use the teleporters!"
Rainbow Dash scoffed, "I've got Foal-Face, I'm compensating for debuffs." before Big Mac picked her up and she yelled, "I can't believe you're doing this! Let go!"
As Big Mac tossed her, he got on the teleporter, "You're the fastest flier in Cloudsdale, you don't need the teleporter."
Soon enough, Pinkie returned to see the two ponies fighting on the teleporter, Rainbow Dash was on top of Big Mac hitting him in the head. As the teleporter started to activate, she said, "Hey, you two quit that before you-" only for the teleporter to activate, and end up breaking, "God dang it!" before running off to find her teammates on the other side.
As they came out of the teleported, Big Mac said, "Ugh, I don't feel right..."
Rainbow Dash groaned as she rubbed her head, "It feels like I've got a hippo sitting on my ribcage..."
As the two ponies looked at each other, they realized they were looking at their own body, both of them saying, "Spy!"
Before Rainbow Dash said, "No, Mac?"
And Big Mac said in union, "No, Dash?'
Rainbow Dash started panicking, "That's impossible! We must have done something to the teleporter!"
Mac grumbled and said, "I need a fritter."
Rainbow Dash growled, "Oh no, I can feel the cinnamon in my lungs, you ain't ruining my bod!"
As Pinkie came in, she yelled, "What the ding dong were you two thinking!? The teleporter will only accept one pony at a time! Now what if you two ended up fused together? Or Tartarus, with scrambled brains!?" When Rainbow and Mac acted normal and laughed, she giggled as well and said, "We have fun. All right you two, back to work."
As Pinkie left, Rainbow said to Mac, "We'll tell hard hat about our problem, but not now. They might think we're spies."
Mac nodded, "Eyup, but I'm me, and yer you. How can we be each other? We both have different strategies."
Rainbow chuckled, "Come on, we've been working together for years now, how hard can it be?"
Contrary to Rainbow's initial thoughts, it was much harder than they thought it would be. Big Mac couldn't get the hang of Rainbow's wings, and often ended up crashing into something.
In the mean time, Rainbow had forgotten that her Criti-Cola didn't work on Big Mac's body because of how big he was, and ended up trying to make jumps that his body had no chance in making.
Meanwhile, Rarity noticed something was obviously wrong and told Derpy, "Derpy, gather up our friends. Rainbow Dash and Big Mac are spies, and we need to interrogate them and find out where the real Rainbow and Mac are."
Big Mac and Rainbow Dash were walking back to the base and Mac asked Rainbow, "Don't ya think we should tell the others about our little problem?"
Rainbow Dash shook her head, "Not yet, we just need to act-" before being hit on the back of the head with Derpy's mail box weapon, and being knocked out cold.
As Big Mac realized what was happening, he too was knocked out by Rarity with a cloth and chloroform. When they came to, they were tied with their front hooves behind them, and Rarity spoke, "All right, what have you two terrible spies done with our friends? Speak!"
Rainbow Dash in Big Mac's body was able to get out of the cloth holding her hooves together, even though it was by accident, "Wait, we can explain!"
Rarity growled, "You have lots to explain. Derpy!"
Depry snapped up to her hooves with a shotgun in tow, "All right sister! Prove that you're not a spy! What's your first name?"
Rainbow Dash knew how easy it was to confuse her teammate and said, "Well what's yours you dumbass?"
Derpy's crossed eyes went wide and she whimpered, "Dear Celestia! I've been a spy all along! I'm a disgrace!"
Rarity knocked the gun out of her hooves, preventing her from blowing her own head off and said, "You two have ten seconds to explain yourselves!"
Spike had started to get his flamethrower ready while Applejack broke an empty bottle of cider to use as a weapon. Soon enough, Pinkie burst in and said, "Stop! Cut it out Rarity! Call Spike and Applejack off now!"
Rarity was shocked that Pinkie was standing up for who she believed to be spies and said, "Pinkie, have you gone completely insane!? These two spies have done something with our friends, and you're defending them!?"
Pinkie slapped Rarity's gun out of her magic grip and yelled, "They're not spies, you snail sucking dumbass! These two morons were fighting on the teleporter a few days ago. I realized they put the space fluctuater out of line. They're not spies, they're two dumb minds who swapped bodies. Ain't that right?"
In Rainbow Dash's body, Big Mac said, "Eyup, Pinkie's right"
Pinkie untied the two of them and said, "Come on you two, let's get this fixed." before leading the two of them to another set of teleporters, and as Big Mac in Rainbow Dash's body sat on top of Rainbow Dash in Big Mac's body, they got on the teleporter and were quickly teleported again, restoring their minds to their proper bodies.
Rainbow Dash chuckled, and said, "Hey thanks Pinkie. Feels good to be back in my own rocking bod again." before looking at Big Mac and saying, "I should be saying sorry to you too. I never realized how hard it was being you."
Big Mac nodded, "Eyup, being you wasn't easy either though. Come on, let's get going."
As the two of them got to the door and didn't have enough room to both go through, Rainbow said, "Why don't you go first this time?"
Big Mac shook his head, "Nope, you go first."
Rainbow Dash grumbled, "No way man, I was first the last time!"
Soon enough, the two of them were arguing in the same way that got them into the body swapping mess in the first time. As Rarity and Pinkie watched, Rarity sighed, "When will this idiocy end?"
Pinkie sighed as well and said, "I think we're just getting started. Maybe fusing them together would teach them a lesson."
Rarity face-hoofed and said, "Don't even think about it Pinkie, I've had enough of this for one day."
The End...