Presented in IMAX
Rainbow had never gotten to Canterlot faster. She had to admit her new size was impressive. Not only was she the fastest pegasus in Ponyville, she was now udoubtedly one of the biggest. She refocused herself on the task at hand quickly. Twilight had informed her of the situation in Ponyville and after checking Cloudsdale, Canterlot was the next likely place to find Fluttershy. As Rainbow noticed the huge hoofprints in the pavement leading down the street, she knew she had been correct. She followed the trail down the road, being careful not to accidentally step on something or somepony.
"Rainbow Dash! Rainbow Dash!" Discord called out to her, Luna trailing behind him with a slow, awkward gait. Rainbow Dash turned to face them both. Discord seemed to be carrying... a camera?
"Princess? Discord? Wha-what is this?"
"Oh this is wonderful! Two giant pegasi? This will make for a fantastic action sequence!" Discord said, setting up the camera and rolling the film.
Luna swayed from side to side as she stood in place. "Rainbow... Dash... why are there... three of you?" Still disoriented from being crushed by Fluttershy's massive flank, the image of a giant Rainbow Dash blurred in and out of Luna's vision.
"Three of- what are you doing here? Why is Discord free?"
"Please Rainbow, stop moving... I'm having... difficulty enough with the floor moving."
"It's quite all right." Discord said, taking a moment to look up from the camera to explain. The camera kept filming despite the fact he wasn't rolling it anymore. "To be honest, I'm not quite sure how I got out but once I did, I found an all too giant Fluttershy. Seems somepony's been experimenting with size-altering magic."
"Yeah..." Rainbow Dash said, thinking back. "Twilight's working on a new spell. We think it may have hit Cloudsdale and gigantified all the pegasi."
"How did she hit Cloudsdale with a sizing spell?" Discord asked.
Rainbow's gaze shifted to the side as she prepared to reply. "We think... she might've missed what she was aiming at and accidentally hit the city." Discord covered his mouth to stifle a laugh as the two ponies glared at him.
"So now ALL the pegasi are giants?" Luna asked as she finally regained clarity.
"That's what it looks like. Twilight THINKS she's figured out a spell to fix everything but we need all the pegasi back at Cloudsdale to do it." Rainbow said.
"So you came here to get Fluttersy?" Luna guessed.
Rainbow Dash looked around. "Yeah, we need to get her back to Cloudsdale so Twilight can use her counter spell. Where is she? Is she around here?"
A large crash from blocks away drew the group's attention. "You could say we've seen her around. Especially Luna..." Discord said.
"Don't". Luna replied.
"Well, she shouldn't be too hard for me to find. What are you two going to do?" Rainbow Dash asked.
Discord pulled out a giant pocket comb. "Let's comb the city!" he proclaimed.
"I don't think that will be necessary. We should just follow the... chaos." Luna said in an almost defeated tone.
Discord smiled a toothy grin. "I do have an ear for that sort of thing don't I? Let's get going everypony! We've got a giant to catch!"
Rainbow Dash carefully used her hooves to prop herself up and look over the roofs of a building. The buildings were a bit taller than the ones in Ponyville. She looked across the city, scanning the tops of buildings for any sign of Fluttershy.
"You see anything?" Luna asked.
The giant rainbow pegasus turned, momentarily perplexed. "Why are you asking when you can-"
"I found something!" Discord announced as he raked the street with a comb. He reached down and pulled up a long, over-sized strand of hair.
"A hair? It must've fallen off her when she came by."
Rainbow Dash leaned over and examined the giant follicle. "That's not Fluttershy's; her hair is pink, not gray. Wait," Rainbow Dash's eyes went wide. "You don't think... Derpy!" she called out. The thought of a giant Derpy Hooves inadvertently destroying Canterlot ran through their three heads at that moment. Luna shook it off.
"Rainbow Dash, there's something we should explain." Luna began.
"What is it?"
"That hair might still be Fluttershy's."
Rainbow Dash raised an eyebrow. "How? That spell doesn't cause agint too does it?" Rainbow pulled down her own hair with a free hoof and examined her own mane.
"Not exactly... you see, Discord..." Luna looked over at the draconequus holding the giant comb. He froze in place. A shadow fell over him, as did a piercing gaze from the enormous rainbow pegasus nearby.
"You wouldn't have anything to do with this... would you Discord?" Rainbow asked in an accusing manner. Discord smiled sheepishly.
"Discord..."
"I couldn't help it! I mean seriously! It was just such a.. huge opportunity! How could I pass up something so... massive?" Discord justified his chaotic actions the only way he could.
Rainbow Dash stomped a hoof into the ground, shaking the pavement. She snorted a gust that knocked the comb out of Discord's claws before lowering her head to his level and meeting him face-to-face.
"You are going to change her back as soon as we find her!" Rainbow declared. Discord, in a moment of panic, pressed a thumb to Rainbow's forehead in an attempt to deharmonize her. Gray started to spread over her coat and a part of her mane as Discord's magic worked to switch her personality but Rainbow's gaze remained firmly fixed on him directly in front of her. The gray quickly receded into Discord's claw. He pulled it back as if he'd been stung and sucked on the claw, trembling as he did so.
"Don't try that again." Rainbow said. Discord nodded, jittering as he did so.
"You are going to help us find her, change her back and then bring her to Cloudsdale. Understand?" Rainbow made it clear for him one more time.
"Yes ma'am." was his only reply.
Luna thought about the hair in the middle of the road. "Oh! I just remembered. She said something about going to find some new seeds somewhere in Canterlot. She asked me if I knew of any shops nearby."
Rainbow Dash stood up. "Lead the way Princess. To the nearest florist." Luna took to the sky with Rainbow following her on the ground and Discord once again at a safe distance behind them carrying the comb with him as he ran.