After making sure all the doors and windows to the Golden Oaks Library were locked, Twilight Sparkle turned back to her friends.
"Okay, so do you remember the royal wedding?"
Rarity gasped as Twilight's words brought a spark of realization, "Changelings! Of course!"
"Are you trying to say that the whole town got replaced with Changelings in a single night?" Applejack questioned before her voice grew louder, "Did Changelings foalnap my sister?!"
"Ooohhh... Yeah, the wedding..." Rainbow Dash nodded her head slowly as she averted her gaze, "Yep, I remember all of it!"
"..." The group turned to look at Rainbow Dash, all noting how suspicious she was acting.
"Is there something you wish to tell us, Rainbow Dash?" Rarity asked, "Because I can assure you, if you have some piece of valuable information that could save my sister right now and you're refusing to share it, why, I might never forgive you for it." Rarity stared intently at the Pegasus, trying to get a read on her friend.
"Okay, so... I might not really remember the Wedding that well~" Rainbow Dash tried to dispel the growing tension with a smile.
"How come?" Spike asked as he climbed up to sit on a table, "The entire thing was like super memorable!"
Seeing the looks on her friends' faces, Rainbow Dash let out an embarrassed groan before she explained, "Look, I don't remember much after I had Pinkie's Tutti-Frutti Sherbet Sugar Punch, okay! Everything was kind of a blur afterwards..." Rainbow Dash told them before giving herself a mental note to stop eating Pinkie Pie's food without first asking what's in it.
"That's because I use seven parts Sugar to every one part Tutti!" Pinkie Pie said with a cheerful smile, happy that her friend remembered the food she had made back then.
"We're getting off topic here!" Applejack told the group before turning back to Twilight, "Changelings, Ponyville, Missing Sisters, what's next?"
"We need to warn Princess Celestia about what's going on. She'll know what to do!" Twilight Sparkle told her friends before she turned to the baby dragon of the group, "Spike! Take a letter!"
"On it!" The baby dragon said, already holding a quill and ink.
~Three rewrites and a spell check later~
"Perfect! Send it to Celestia, Spike." Twilight told her younger brother, happy with how her message turned out.
"No problem," Spike told her before he opened his mouth and engulfed the letter in green fire, smiling as he watched it disappear into magical smoke, only to immediately burp out a similar puff of green fire as another letter appeared in front of him.
"Now that's what I call service!" Pinkie Pie said cheerfully at the speed in which the letter was answered as Twilight pulled the letter towards her to read its contents.
"Dear Correspondent: I am unavailable due to a royal emergency. Please try sending your letter again at a later time." Twilight read the letter out loud, "I... I was just form lettered?!" She yelled in astonishment.
"Well, looks like we are on our own for this." Rainbow Dash pointed out before she slammed her hooves together, "Time to kick some butts!"
"Um... I think I would be okay with waiting until the Princess is available again..." Fluttershy said softly, trying her best not to imagine what would happen to her if she were caught by the changelings outside.
"My sister is missin', and if those things are responsible, we need to find out what the hay is going on!" Applejack told the group, "With or without the Princess helping us!"
"We can't just go out there!" Twilight pointed out, "They'll know we aren't changelings! We need a plan."
"Oh! Idea! Idea!" Pinkie Pie began raising her hoof, jumping in place, trying to get Twilight's attention, "Pick me! Pick me! I have an idea!"
"..." Twilight felt her shoulders hunch as she sighed tiredly, "Yes... Pinkie?"
"Okay, Girls!" Pinkie Pie paused before nodding at Spike, "And Dragon..." Pinkie Pie continued, "We are going to blend in. We are going to sneak behind enemy lines!"
"First, I want you to clear your mind," Pinkie told her friends before her eyes started to droop, as if she stopped thinking about what she was doing, "Then I want you to walk like a zombie!" She continued, tilting her head slightly to the side before she began shambling around with a slight limp, as if struggling to move, "Then I want you to... Erm... Groan? No, it's more of a moan, like... Like you're a Zombie trying to say Braiiinnnnzzz~ But like, not saying it, so you just go Bleeeeeehhh~ You know?"
Whether she noticed Rarity hoofing her face, or Rainbow Dash's look of astonishment at how she didn't think of that plan sooner, Pinkie Pie didn't show it as she continued to shamble around the library like a zombie, "Let's do this." She said in an undead moan as her friends joined her in pretending to be mind-controlled.
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"I think it's working!" Pinkie Pie said with a smile as the group made their way down the now eerily quiet streets of Ponyville.
"Shh!" Rarity admonished Pinkie with a loud whisper, "Blank! No smiling!" She reminded her of the plan, watching as Pinkie smiled apologetically before returning to her zombie-like shuffle.
"Uhh... Everypony?" Twilight Sparkle called to the group before pointing at something up ahead.
The group watched with zombie-like stillness as a mind-controlled Pegasus walked up to a nearby tree before two of the rocks near the foot of the tree erupted into green flames, transforming into a pair of changelings who quickly covered the Pony in a cocoon of quickly hardening green saliva.
Once the cocoon was hard and solid, with the pony inside no longer able to move, one of the Changelings shapeshifted into the Pegasus, a wicked smile on their now fur-covered faces as they looked down at the captured pony before the second Changeling picked up the cocoon, preparing to move it somewhere else.
"Hey, who're those?" The group froze as the Changeling-turned-Pegasus noticed them, pointing out their location to the other Changeling.
"Huh?" The Changeling hummed, roughly dropping the cocoon he just picked back onto the floor, uncaring for the pony inside, before the duo walked closer to the group.
Twilight felt her fur stand on end, memories of her last encounter with Changelings quickly flashing through her mind as the two changelings looked her over, a weak phantom ache beginning to drum against her ribs from where the Changeling Queen kicked her while disguised as Cadance, only to silently let out a sigh of relief as the two shapeshifters moved on to her friends, seemingly buying into her mind-controlled act.
The next minute felt like an eternity for Twilight, having to hold on to the act while hoping that her friends also succeeded. She was unable to move her head to look at them. All Twilight could hear was their breathing and the quiet movements of the two changelings.
"Probably Stinger's work," One of the changelings said, "Forgot to capture them after he stunned them again."
"Yeah," The changeling in the shape of a Pegasus nodded, "Well, these are his problem, not ours." They chuckled, their predatory smile an unfit match for the soft Pegasus features they now wore.
Deciding that there were no issues for them to worry about, the two changelings flew off, leaving behind the cocoon with the captured Pegasus.
After making sure the two changelings weren't going to turn back, Twilight released a breath she didn't realize she was holding.
"That was way too close for comfort," Applejack said as she wiped a bead of sweat off her brow.
"Th-that was scary..." Fluttershy muttered shakily as she sat down to calm her nerves.
"Where are they keeping all of these?" Rarity asked as she walked closer to the cocoon and looked at it, staring at the Pegasus that was trapped inside, seemingly still mind-controlled if their blank stare was anything to go by, "This is the only one we've seen so far..."
"Uh..." Spike began to speak as he looked away from the group as they gathered around the cocoon, "Do you think where they would be might look weird and pulsing with an eerie green glow?" The baby dragon asked.
"Well, yes, but that would be-" Twilight Sparkle answered as she turned to look at Spike, only to notice him pointing at the Ponyville Town Hall, "-a little obvious..." Her words teetered off as she stared at the slowly pulsing green glow that eerily shone through the windows of the building.
"I think that's where they are!" Pinkie Pie said helpfully as she pointed at the Town Hall.
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A Certain Unicorn was making his way through the Everfree Forest, a duffel bag by his side, an illusion hiding his appearance, and a Red Hot Chili Peppers song whistling from his lips.
"Getting born in the state of Mississippi, Papa was a copper, and her mama was a hippy~"
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"Let's get this rodeo started!" Applejack yelled as she kicked open the door to Town Hall.
"Give me back my sister, you ruffians!" Rarity shouted as she entered the building, her horn shining with a cornflower blue aura of magic.
"Yeah!" Rainbow Dash exclaimed loudly as she entered next, "It's flank whooping..." Her excitement began to slow as she looked at the small mountain of green cocoons and the many ponies trapped within. Noticing that while most were still seemingly mind-controlled, if their blank stares were anything to go by, some were already awake, and weakly kicking at the cocoons inside to no avail. "...Time?"
And from behind the small mountain of hard green spit, several changelings began to crawl out from their hiding places.
"Okay, Girls! We've fought them before, we can handle this!" Twilight Sparkle told her friends, only to watch as more and more changelings entered the now crowded lobby of Town Hall, filling it with dozens upon dozens of the shapeshifting creatures, "...I think?" Twilight Sparkle swallowed the saliva building in her mouth before focusing on the small army in front of her.
There were close to 40 Changelings in the lobby, with perhaps more deeper inside the building.
"What are we waiting for?!" Rainbow Dash yelled, pulling Twilight back into focus, "Let's kick their insect butts!"
"Right!" Twilight nodded, "Girls, let's do this!"
And with a beam of magic escaping Rarity's horn, the fight began.