Plague

Twilight walked contentedly across Ponyville, wearing a bag with a book inside around her back. She had promised Mr. and Mrs. Cake that she would deliver them a cookbook from the library, and she kept to her promise.

When Twilight arrived at Sugarcube Corner, Pinkie Pie's head was already poking out through the door.

"Hi, Twilight!" Pinkie Pie exclaimed cheerfully. "A little birdie told me that you're delivering a cookbook for Mr. and Mrs. Cake!"

Twilight chuckled a little and smiled. "Well, that little birdie was correct." Twilight's horn grew a purple glow as she levitated the book out of her bag. "'The Guide to Cooking the Perfect Chocolate Chip Muffins,' correct?"

"Yessiree!" Pinkie chimed, grabbing the book with her mouth and setting it on a nearby counter. "Oh boy, my mouth is just watering just thinking about those yummy chocolate chip muffins! Although, my tummy doesn't agree." Pinkie frowned and rubbed her abdomen with her front hoof.

Twilight gave her a concerned look. "Is everything alright, Pinkie? Are you feeling okay?"

"Yeah, I'm fine. My tummy is just churning a little bit. I probably just ate too many cupcakes. Mrs. Cake wasn't feeling too good last night; her tummy was upset, too! So, I cooked her a big, big, big batch of cupcakes to make her tummy feel better! And I ate some too! There's some cupcakes leftover - you should have some!" Pinkie Pie trotted off into the kitchen, and quickly brought back a cardboard box filled with six leftover cupcakes.

"Oh, well thank you Pinkie!" Twilight's horn glowed once again as she picked up the box using her magic."That was very kind of you-."

"Ohhhh noooo!" A shrill stallion's voice called out from the back of Sugarcube Corner, his voice just barely standing out from the wails of crying babies. "Dear, grab some towels, hurry!"

Twilight piped up. "What's going on back there?"

"I dunno," Pinkie answered with a confused expression. "Come on, let's go look."

Twilight set the box down on the counter with the cookbook, then she and Pinkie walked to the back of the store to find Pumpkin Cake and Pound Cake crying in Mr. Cake's arms, and Mrs. Cake wiping up a pale orange mess on the floor with a towel.

"What happened?" Pinkie and Twilight said, in sync.

Mr. Cake answered frantically. "The twins just had a little accident. They just puked a little. No big deal, right sweetie? The twins are okay, right?"

Mrs. Cake laughed to herself, rolling her eyes. "Yes, they're okay. No need to worry. Babies spit up all the time." Mrs. Cake threw the soiled towel in a laundry hamper, then washed her hooves. "Although, I was a little nauseous myself last night, and it's still lingering a bit."

"That's what I told Twilight," Pinkie responded. "And I told her that my tummy's a-rumblin' today, too!"

Mr. Cake, still trying to calm his ill babies, answered nervously. "My stomach is a little upset, too. I hope there isn't a stomach bug going around. I don't want any of us to be sick!"

"Don't worry, Mr. Cake," Twilight said in a warm tone, walking back to the front of the store. "This all just seems coincidental. Now, I have to get back to the library. I'm sure Spike will be excited to see the delicious present I'm bringing back!" Twilight levitated the box of cupcakes and smiled back at Pinkie and the Cakes. "Rest up, all of you!"

Twilight walked home, not thinking much of the incident back at Sugarcube Corner. Like she had mentioned before, it all seemed pretty coincidental. However, she did begin to feel a little nauseated as she headed back to the library...

"Spike! Spiiike! I have a present for you!" Twilight chimed as she walked through the doors of the library. Spike came rushing down the wooden steps to see Twilight holding an open box of cupcakes.

"Oh boy!" Spike exclaimed, grabbing a cupcake, marveling at the pale yellow, baked batter and bright pink, sugary frosting before digging his teeth in, admiring the taste just as much. "Mmm, these are good! Did you get these from Sugarcube Corner?"

"Yep, Pinkie gave them to me when I gave her the cookbook." Twilight answered, setting the box down on a nearby desk. Her stomach grumbled, reminding her of what had recently happened. "Although, it was a little strange over there. Everyone there seemed to have had some stomach issues, and when I was walked back here, I started to feel a little woozy, as well."

"Well, don't get me sick." Spike said absentmindedly, finishing the last of his cupcake.

"No worries, I don't think I'm getting sick. My stomachache was probably just somatic from seeing all of them not feeling well. I'll check on them tomorrow-." Twilight got cut off with a sudden coughing fit. She cringed as her throat violently contracted.

Spike looked up at Twilight, concerned by her sudden coughing. "Twilight, are you okay?" He said, trying to shield his face from each cough.

Twilight cleared her throat. "Yes... I'm fine," She said, coughing in between every other word. "Just... A little... tickle in... my throat..."

Spike wasn't too convinced. "Okay... But, like I said, don't get me sick." He grabbed another cupcake from the box on the desk and walked back up the stairs.

Seconds later, Twilight's coughing fit ended, although she still felt more and more nauseated. Still convinced in her mind that this was all a coincidence, she went on about her studying, coughing here and there and stopping to rub her churning stomach.