Sand

Rainbow dash opened her Magenta eyes. Birds sang, and flew in the light breeze, acting as an alarm clock for the cyan Pegasus. She rolled over and put her face in her pillow, trying to block out the irritating noise that woke her from her peaceful slumber. She yawned and squeezed her eyes shut tighter, but suddenly they opened. Rainbow Dash remembered something very important. The realisation slapped her in the face, as a wide grin began to form across her sky-blue face. Today was her birthday. No work, no moving clouds. Just her and her friends having some fun together. As much as she was excited to see her friends, the Pegasus also couldn't wait for the presents, who wouldn't? She dashed to the downstairs of her cloud house, where she began to devour her breakfast which she had made in ten seconds flat. The Pegasus rushed around her house, getting ready for her big day.

After she was ready to go, she opened the front door, then leaped into the air. White, fluffy clouds evaporated into nothingness as the cyan Pegasus charged into them. The cool air from the clouds felt nice against the scorching heat of Celestia's sun as she shot towards Twilight's cast-- er, home.

Dash landed, causing a cloud of dust to rise from the dry earth. She shook her entire body, slightly irritated, but the irritation didn't last long as she remembered that today was her big day. Nothing can bring you down on your birthday!

Rainbow knocked on the large, crystal door, waiting for her friends to open it and let her in. Her tail swished from side to side as she became more and more impatient. Rainbow Dash was a pony of action, she was only interested in the things happening right in front of her, and a door wasn't the most interesting thing in the world.

Bored and impatient, the cyan Pegasus made her way towards the centre of Ponyville, guessing that her friends had gone to Sugar Cube Corner. She walked this time, looking around at the quiet town. It wasn't a Saturday, so she wasn't expecting anything out of ordinary anyway. Secretly, she had hoped for something to happen, anything to cease the mind-numbing boredom she was feeling. Several kind ponies smiled and wished her a happy birthday on her way to the building of sweet delights so delicious and moreish, that even looking at them was enough to make somepony feel sick. Either way, she continued strolling down the dusty, cobbled streets. Happily waving at many of the ponies who were idly standing by doing normal pony things. Rainbow Dash smirked, one big, bold thought staying right at the centre of all of her thoughts. Today was her birthday. Though, she still secretly hoped that there would be some cool monster attack or something, but it wasn't a Saturday, so nothing was going to happen

Rainbow Dash approached Sugar Cube Corner, taking in the sweet scent if cakes, cooking, and icing, which could all easily be smelled from the outside. She smiled as she opened the door, looking around her she saw several happy couples eating today's special, nothing out of the ordinary. Yet, she felt this sensation of excitement that bubbled in her belly. It slowly spread all across her body, and she felt a little nervous. Like and impeding sense of doom and dread that clung to her. She dismissed the feeling as just excitement for her birthday, and continued scanning the shop for her 5 pastel coloured friends. The cyan mare looked to the corner of the restaurant, but there was no luck there. Instead, she decided it was a lost cause, and that they were probably doing something way cooler than standing around in a very tempting cake shop.

...

Surely one cake wasn't going to do any harm...

Dashie strolled over to the counter, but Mrs Cake was at the back talking to Mr Cake. You could hear them struggling to keep Pumpkin and Pound under control from the counter. She waited for about five minutes, awkwardly tapping her hooves against the creaky wooden floor. Eventually after what felt like hours, but was probably less than ten minutes, Mrs Cake hurried downstairs and immediately apologised. She started explaining why she was upstairs, but \Rainbow Dash wasn't listening. She was focused on something that was moving, hidden underneath a greenish blanket.

"H-hey, what's that?" Rainbow asked inquisitively, pointing to the shrouded object. Mrs Cake smiled,  and hurried over to it. Then she grabbed the blanket and yanked it off.

Rainbow Dash flinched, expecting some kind of monster to jump out and attack her or something. Instead five pastel coloured ponies jumped out, all shouting "SURPRISE!" in what was meant to be unison, but was all out of time and ended up sounding completely dreadful. Rainbow Dash generally looked surprised at seeing them, and completely forgot about ordering. Instead she ran over and hugged all her friends, who had begun singing an out of tune "Happy Birthday!" song. After the song was over, Twilight smiled, and went to tell Rainbow Dash what they had planned for her special day, but just as she opened her mouth to speak, Pinkie Pie intervened.

"WE'RE GOING TO THE BEEEAAAACH!!" She shouted in Rainbow Dash's ear. For a few seconds, a loud ring was all Rainbow could hear, but her friends were laughing and smiling, probably due to the embarrassed Pinkie Pie's outburst. Rainbow tried to register what her bubblegum coloured friend had said, but she couldn't quite make it out with the distracting ringing in her ears. When the ringing finally subdued, Rainbow Dash thought clearly. Then the words sunk in.

Suddenly the smile on Rainbow's face dropped. The beach was fine, especially the Sun and the sharp, coolness of the water.  But there was one problem: She hated sand.