Rainbow grunted as her forehoof made contact with a cloud. She could feel the cloud dissipate beneath her hoof, and could hear the small poomf as the cloud completely disappeared. Taking a deep breath, Rainbow looked around herself, taking in the perfect summer weather. A gentle breeze ruffled her mane, causing her to smile. It was indeed a perfect day. Perfect for a nap. She thought inwardly, spotting her napping cloud. She quickly looked around her, checking to make sure that her work was indeed done. The weather forecast had called for clear skies, and that was just what she had delivered. Smiling once more, she turned back to look at her napping cloud, her mind awash with the thought of sweet relaxation.
"Rainbow!" A voice called from below her.
Rainbow groaned aloud, and looked down. There, Twilight, Rarity, Applejack, Fluttershy, and Pinkie Pie all stood, looking up at her. Her hopes of a nap gone, she flew down to meet her friends.
"Hey, girls." Rainbow said, as she landed on the grass with a light thump. "What's going on?"
"We were trying to find you to ask you if you wanted to join us! We're going to a concert in Canterlot!" Twilight exclaimed joyfully.
"A concert in Canterlot?" Rainbow thought aloud.
She silently weighed the pros and cons in her head. She didn't want to leave Ponyville, and she wasn't one for concerts, but all of her friends were going, and she didn't want to be left by herself. She suppressed a sigh. "Sure."
Twilight beamed. "Yes!" She squealed, while the others nodded, and made noises of approval.
. . .
Rainbow looked out the window of the train, lost in thought. She never liked concerts, due to the barrage of colors that greeted her vision whenever the band or orchestra began to play. How do the others put up with it? She thought to herself as she looked at her friends, who were talking and laughing amongst themselves. Deciding not to ponder that particular question, she looked back out the window, at the scenery outside.
______________________________________________________________________________________________________________________________________________
Twilight noticed Rainbow looking out of the window or her seat, seemingly lost in thought, with a small frown upon her face.
"Rainbow?" Twilight called to her friend.
Rainbow jumped slightly, and turned to face Twilight. "Yes?" She replied.
"Is everything okay?" Twilight inquired. "You seem upset."
"What? Oh, no. I'm fine, Twi." Rainbow reassured her friend.
Twilight stared at her friend, who had turned back to look out the window. Using her magic, Twilight teleported into Rainbow's seat, drawing another suprised jump from the pegasus.
"Twi, what the hay?!" Rainbow exclaimed, turning around once more to look at her lavender friend.
"Rainbow, what's going on?" Twilight persisted, her eyes boring into Rainbow's. "It looks like something's bothering you."
"I'm fine, Twi." Rainbow sighed. "I was just thinking about something."
Twilight still looked concerned, but accepted Rainbow's answer all the same. "Okay then. But remember. You can talk to me if there's anything bothering you, okay?"
"I know, Twi." Rainbow replied, looking back out the window.
. . .
"Here we are! Oh, it's wonderful!" Rarity exclaimed as they approached the Canterlot Concert Hall.
The Concert Hall was indeed magnificent. It was twice as tall as the Ponville Library, and its big purple doors were open, as if to say 'welcome'. As they all approached, Rarity dashed forward, and grabbed a schedule, flipping through it with haste.
"What music is going to be preformed?" Twilight inquired, as she sidled up to Rarity.
"Oh, Octavia Melody is going to play something called 'The Rains of Castamere' on her cello, then Vinyl Scratch is going to play some- eew... 'Hardcore Dubstep' music with her... Equipment."
Rainbow winced at the term 'Hardcore Dubstep'. For her, it wasn't just painful for her ears, but what she saw was worse. She had half a mind to turn and run, but she had agreed to come with her friends to this concert, and she wasn't about to back out of her agreement.
"Well, we came here." Twilight sighed. "Let's go, girls." She said, as she stepped into the concert hall.
. . .
Rainbow sat patiently, as Octavia's last bow stroke ended her song. It was an okay tune, but it was rather sad in her opinion. Still, it was bearable.
"Now, presenting... Miss Vinyl Scratch!" The MC stated loudly.
Vinyl came onto the stage, a smile on her face, and her glasses covering her eyes, like usual. She happily trotted over to her equipment, and sat down. She took out a disc of sorts, and inserted it into her equipment. Rainbow braced herself, as Vinyl made a move to play.
______________________________________________________________________________________________________________________________________________
Once the music started to play, a barrage of colors met Rainbow's vision. She slapped her hooves over her ears as waves of sickly green, gold, grey, dark blue, and black swam in her vision, churning, and spinning. Rainbow felt like she was about to hurl as she stood up, and staggered over to the exit. She blindly felt for the door, ignoring her friends cries. Upon touching the door, she forced it open, and stumbled out into then open air. She inhaled as deeply as she could, trying to block out the music that was oozing from the Concert Hall. She could hear her friends voices, however they were muffled by the pounding of music. After a few more seconds of deeply inhaling, she heard the doors close with an almighty slam. Just like that the colors that danced in her vision dissapered. She gasped for more air, as her friends came galloping over to her.
"Rainbow!" Twilight exclaimed, "What happened back there?"
"How..." Rainbow asked, still queasy. "Do you guys put up with that?"
Twilight looked at her friend curiously. "The music? Well it's not the most pleasant noise in the world but-"
"I'm not talking about the music, Twilight." Rainbow interrupted, spinning around to face her friends. "I'm talking about the colors. They're as annoying as Tartarus, and... Why are you looking at me like that?" She inquired, looking at Twilight with a conserned expression on her face.
Twilight looked completely alarmed as she took a step back from Rainbow. She took a deep breath, attempting to calm herself down.
"Rainbow." Twilight began, as calmly as she could possibly sound. "Have you had anything strong to drink lately?"
Rainbow's look of concern became one of outright confusion. "No. Why, Twilight?"
"Ponies don't randomly see colors, Rainbow." Twilight told Rainbow, as if she were talking to an obnoxious school filly.
"It's not random, Twilight! And don't be dumb! You can see them, too! Just, how do on out put up with it?!" Rainbow whined.
"I don't see colors, Rainbow." Twilight replied. "It's not possible to see them appear like that."
"Actually..." Rarity piped up. "Do you see random colors whenever you hear a sound?"
Rainbow silently nodded her head, her attention now focused on Rarity.
Rarity gasped, a look of awe on her face. "Why darling, you simply have Synesthesia!"
"Synesthesia?" Twilight turned towards Rarity, a look of confusion now plastered on her features.
Rainbow said nothing, she just simply looked at Rarity with the same look of confusion as Twilight did. What was Synesthesia? Was it normal?
Rarity looked at Twilight with a surprised look on her face. "You've never heard of it?"
Twilight shook her head.
"I read about it in a book Spike gave to me, the little dear." Rarity began.
Rainbow rolled her eyes. The little dear? She repeated in her head.
"Synesthesia is where one of the five senses in our bodies is connected to another, to a degree." Rarity began. "For Rainbow, it links color to sound. So when she hears music playing, or like right now, she is hearing me talk, she will see different colors, depending on the pitch of what she is hearing."
Twilight stared slack jawed her friend, then turned towards Rainbow, who looked equally as shocked. "Then why didn't she know of what she had?" She inquired, turning back towards Rarity.
"Twilight, Rainbow has lived with this since she was foaled. To her, seeing sound is perfectly natural to her just like not being able to see it is quite natural for us."
"So... You can't see sound?" Rainbow piped up in a semi-quiet voice.
One by one, her friends shook their heads.
"Oh." Rainbow muttered.
"Don't be discouraged, dear." Rarity quickly said. "I'm actually quite envious that I can't see what you see."
Rainbow's heart seemed to lift a little at that. Even though sometimes her 'Synesthesia' could be quite annoying, it was nice to know other ponies appreciated it.
"Well now that that's out of the way..." Twilight began, "Shall we head out for some lunch? I don't think any of us want to go back into that concert hall."
There were cheers of agreement coming from all of her friends. Rainbow smiled once again, as she followed them over to a café. She had learned a lot about her view in life today, that she was unique, different, from other ponies. She could see sound. She could see things that other ponies could only dream of seeing. Yet for her, it was a reality.
Author's Note
This is what you get when I create a story and don't write it down first. XD I hope you enjoyed it. 
I do not own the Rains of Castamere. All credit for that song goes to the original creators.
