Pinkie Pie rarely shouted.
Well, actually, that was a lie. She shouted pretty often. She'd shout out cheerful hellos to ponies on the street, or giddy exclamations of surprise to the lucky recipients of her surprise parties, or to nopony in particular because she just felt shouty.
It was probably better to say that Pinkie Pie rarely shouted with a negative intent; a fact which made the shouting battle that the Cakes overheard that night all the more strange.
"Fancy!" Rarity exclaimed.
"Fun!" Pinkie yelled back.
"Fancy is fun!" Rarity replied, stomping one hoof.
"Nuh-uh!" Pinkie retorted. "Remember the Grand Galloping Gala? None of us were happy with how that went!" Rarity hesitated. There was no arguing that last comment; that had been a debacle of epic proportions. Still, she remained undaunted.
"That was a special circumstance," Rarity said simply. "Just because one fancy occasion was a disaster doesn't mean that every single one shall be."
"But this is Nightmare Night!" Pinkie exclaimed. "It's all about scary monsters and creepy costumes! Everything about it screams silly! Including me! SILLY!!"
Rarity, despite her frustration, couldn't help but smile a bit at Pinkie's little bit of silliness. Even when she was annoyed with her marefriend, she still appreciated her humor and her oddities. This, however, would not make her waver from her point.
"Darling," the fashionista said. "A Nightmare Night soirée can be sophisticated. Why, the ponies of Canterlot hold plenty of them! And I wish to hold one in the same vein. You have plenty of wild, silly parties. Certainly we can make this one exception."
Now it was Pinkie's turn to hesitate. As much as she wanted a nice silly party, Rarity was correct. They did throw a lot of Pinkie's kind of parties. This might even have been a good enough point to make Pinkie reconsider, but she had already told so many ponies about this party and what it would be like. To change it now would be a disappointment.
"I'm sorry Rares, but I can't give this up!" Pinkie said, crossing her forelegs. "I've already told other ponies what kind of party it's gonna be! If I changed it now, I'd be a big mean tell-ponies-one-thing-and-then-something-else-happens-instead meanie-pants!"
"Well, it just so happens that I, too, have informed ponies of what type of party this will be," Rarity responded coolly. "So if we were to do it your way, that would make me a...that thing you said!"
"Well then!" Pinkie said. "We're just gonna have to draw a line in the middle of the room and have two separate parties!"
"Fine!" Rarity shot back.
"FINE!" Pinkie answered. The two turned away from each other in the bed, pulling their sides of the blankets over themselves. There was about five seconds of complete silence.
"...I don't want to go to bed angry at you!" Pinkie yelled, still sounding very much angry.
"Neither do I!" Rarity shouted back with the same emotion.
"I love you!" Pinkie bellowed.
"I love you too!" Rarity screamed.
"Just go to bed, please!" came Mrs. Cake's shout from the other room.
"Fine!" both ponies shouted, and then they did just that.
~~~~~~~~~~
The ponies who attended the Nightmare Night party at Sugarcube Corner were treated to one of the strangest parties they'd ever seen; a situation that was truly telling, considering the odd parties that Pinkie had thrown in the past. One side of the party room was decorated in a very childish-looking decor, the walls covered with paper ghosts, spiderwebs, and other such knickknacks. The ponies on that side were all dressed in silly, over-the-top costumes and having a fine time. On the other side, all the silliness stopped, replaced by fancy decor. The ponies on this side had eschewed typical Nightmare Night costumes in favor of intricate paper masks that they held by a stick in front of their faces. Both parties went on, seemingly in defiance of each other.
The strangest bit might have been the party hosts. Even though Pinkie and Rarity were still slightly peeved at each other, they carried on with their original costume plan. Both ponies were dressed in Two Face-esque costumes; half themselves and half the other. They had dyed half of their bodies in the other's color, styled their manes and tails similarly, and had even gone as far as to paint the other's cutie mark over their own and put in a contact of the other's eye color. Pinkie had even fashioned herself a prosthetic horn. Neither spoke, and their costumes were so good that nopony could even tell who was who. The costumes had been planned weeks before, and yet, given the dual nature of the party, they seemed custom-made for the occasion.
Both hosts watched the party guests dutifully, paying careful attention to which side each party-goer went to and how many guests were on each side. The border was the point of the most contention, and was strictly policed. If a pony from Pinkie's side crossed to Rarity's, one of the hosts would strip them of their silly costume and give them a masquerade mask. The opposite happened for ponies who went from Rarity's side to Pinkie's. Ponies were being stripped and clothed left and right, and the whole thing was starting to get more than a bit confusing.
Pinkie and Rarity stood face to face at either side of the room, straddling the borderline. Each had a confident grin on their face, which only compounded how difficult it was to tell them apart. Party-goers found themselves somewhat entertained at the way they were stationed, as their Rarity sides were on the Pinkie party side and vice-versa. That brief moment of entertainment was often followed by a quick forced costume change from one or the other. After a good hour or so of this, though, the two hosts began to notice something.
"Is it me, or are the guests not having much fun?" one host asked, in a voice that was either Pinkie's or an excellent imitation of it.
"It does seem that way," the other host said in what was either Rarity's voice or a perfect facsimile.
"We've been paying so much attention to trying to prove that our side is the most fun..." said one.
"...That we've neglected the fun of our guests," the other finished. The two stared at each other, ashamed.
"I'm sorry, Pinkie," the first said.
"You're Pinkie, darling," the second said with a smirk.
"Oh, right," Pinkie said. "I'm sorry, Rarity."
"I'm sorry too, Pinkie," Rarity replied. The two shared a hug, then turned to the guests.
"Attention, everypony!" Pinkie shouted. "Forget this whole two parties thing!"
"Yes!" Rarity added. "You may party wherever and however you wish, without worrying about any forced costume changes!" The guests all cheered and spread throughout the room.
"Fancy is okay sometimes," Pinkie said with a smile.
"As is silly," Rarity replied. The two beamed and shared a long kiss, one which was only stopped when Pinkie started to giggle.
"Whatever is so funny, Pinkie?" Rarity asked.
"If I only open this eye, it looks like I'm making out with myself!" Pinkie laughed. Rarity just rolled her eyes and pulled her back into the kiss.
