As Twilight waved a goodbye to the larger group of ponies that she called her friends, she led Pinkie away from the main chamber of the castle. Away from the space where anypony could walk in, looking for guidance from Princess Twilight, and interrupt this moment. She couldn't have that, not now, when she had her mind so dead set on what she wanted to do. No, instead, she led Pinkie down a set of crystallized stairs and into a large room with various instruments of scientific purpose.
A memory flashed through the mind of the pink pony, one of her attached to a big machine as Twilight tried to figure out how her Pinkie sense worked. A shiver ran down her back at the thought. It was all fun and games that time, but the mood of this room was totally different. It was darker, and the machines all looked much more sinister, with sharp jagged edges that jutted out at various angles. There were also tools and other scraps that lay haphazardly around, which seemed out of place for someone that loved organization as much as Twilight Sparkle did.
"Excuse the mess." Twilight said as she saw her friend looking around at the mess of wires and metal strewn about her lab. "I haven't really had time to clean with all my duties, and it's far too dangerous down here to have Spike clean up. We all know how clumsy he can be sometimes." she said, her ears lowering slightly as she felt a small pang of guilt for talking bad about her friend like that. "I just have a few questions though, don't worry, we won't be down here long." she continued.
Pinkie turned her back to the room that was giving her an ominous and sickly feeling, and faced Twilight. "Well, ask away Twilight. What can Auntie Pinkie do for you?" she asked, returning to her usual chipper self.
"Do you remember the incident with the mirror pool?" Twilight asked, taking a slight step closer to her friend.
"Pinkies everywhere sounded like a better idea than it was." Pinkie said, ears drooping and hair slightly deflating.
Twilight adopted a sympathetic look at her friends sad expression. Sadness looked so out of place on Pinkie Pies face, and it brought discomfort and sorrow in the same way that her smile would bring happiness to all who saw it.
"Don't worry about that now Pinkie, there was no way you could have known all of that would happen. None of us blame you." she said, offering a smile to her friend. "Do you think you can talk about it, or are you uncomfortable with the subject?" she asked. Sure, she wanted to find out all she could about the pond, but not if it brought harm to those she cared for. The thought alone brought a shiver that shook her whole body.
Pinkie slowly regained her usual form, and took a breath. "What do you need to know?" she asked simply, wanting to get this done as fast as possible.
Twilight let a tender smile cross her face to show thanks to her friend. "Do you remember how many copies you made?"
Pinkie stuck her tongue out and scrunched up her nose in an attempt to focus her memories from that day. After a few moments, she sighed and looked at Twilight. "Sorry Twilight, there were way too many. I didn't even make all of them myself. You didn't count them when you were zapping them?"
Twilight sighed as well. "No, I was too focused on trying to find the real you to pay attention to much else. It's fine though, I have other questions."
"Shoot away." Pinkie shrugged.
"How did you feel when you made the first copy?" Twilight asked, her horn now glowed with magic as she levitated a notepad and quill from the nearby table so she could take appropriate notes. This was a scientific investigation after all.
"I was super-duper happy!" Pinkie said ecstatically as she remembered seeing the first Pinkie copy she had made. It was like getting a new sister after all these years, and one that was just like her. "Yea! What the writer just said!"
Twilight let her quill come to a halt. "Excuse me?" she asked, confused as to what her friend was talking about.
Pinkie giggled. "Oh, nothing Twilight."
Twilight watched Pinkie for a moment, trying for what felt like the billionth time to wrap her mind around the pink enigma, before she resumed her note taking. "Ok so you still felt like the same old Pinkie then?" she asked in order to confirm her observations thus far.
Pinkie nodded. "Yep yep yep."
"And how would you say you felt after, let's say, the tenth copy?" she asked.
Pinkie put a hoof to her chin and squint her eyes together. "I would say that I felt like jello."
Twilight stopped her note-taking once more. "Jello?" she asked, not understanding at all.
"Yea, I felt like my insides were there but I was all wibbly-wobbly!" Pinkie said, emphasizing it by standing on her hind legs and rubbing her hooves over her stomach.
Twilight raised an eyebrow at this, but continued jotting down her notes. "So would you say you still felt happy?"
Pinkie sat down to ponder this new question. "I was happy, but I was starting to get a little worried." she replied.
"Uh-huh, just as I thought." Twilight muttered as she wrote something down.
"What do you mean?" Pinkie asked.
"One last question Pinkie, then we can stop talking about this." Twilight said, no longer bothering with taking her eyes off of the notes that floated before her. "When the final copy was made, we could all see how sad you were. You were nothing like the usual Pinkie Pie, which is why none of us knew it was you. But, when the copies were all gone, you were pretty much back to your usual self. Did you feel happier as each clone was zapped away, like a piece of you was returning bit by bit?" Twilight asked, urgency in her voice as she asked the big question that would solidify her theory.
Pinkie had to think hard about that one. When she was gathered together with all of her copies, she was so preoccupied with trying to prove she was the real Pinkie that she hadn't paid much attention to what she was feeling. She remembered feeling sad when all her copies were running wild, and she was really happy when they were gone, but her memory was a bit fuzzy. "Wait..." she said, recalling that long day with more clarity than she had ever done before. Yes, she could remember it now. She didn't notice it at first, but when about half of her copies had been zapped away, it felt like a weight had been lifted from her shoulders and a growing darkness has been snatched from her heart. "I...yes. I felt much better when they were all gone. Happier. More like...me." she said as she slowly came to the realization.
Twilight quickly finished writing her notes, and levitated the pad and quill back to the table from where she got them. She walked to her friend and placed a comforting hoof on her shoulder. "Thank you Pinkie, are you ok?" she asked, concerned for her friend whom she just made relive a traumatic experience.
"I...yes Twilight, thank you." Pinkie said with a small sniffle as she licked a stray tear from her cheek. "So did you get everything you needed to know?" she asked, still unsure of what Twilight was getting at with all of this information.
Twilight nodded. "Yes, and I couldn't thank you enough either!"
Pinkie couldn't help but smile. Bringing happiness to her friends lives was what she lived for. "Great! So, what did you find out?" she asked.
"There's something weird about that pond, obviously, but I never had the time to investigate it with everything that happened." Twilight said. "I could always think about it though, a mind is a terrible thing to waste so I'm always using mine. I was able to piece together that each copy you made in the pool wasn't actually a copy, but a piece of you! Of course, I had no solid evidence of this, and I do still have tests to run, but I am sure that I'm right."
Pinkie tilted her head to the side. "I don't get it." she said simply.
"Twilight took a moment to gather her thoughts before she launched into her explanation. "Well, you see, all ponies are born with potential. We think of this as our special talent that eventually shows itself through our cutie marks, but that isn't the only potential we all have. We all have the potential to be good or evil." she paused to take a breath. "Most ponies don't realize it, since we generally all get along, but nopony is ever really born to be good or evil, it's all up to how our lives play out. How we are raised, our environments and our friends."
"But Twilight, I've never felt evil." Pinkie said.
"My point exactly!" Twilight exclaimed with a burst of excitement. "You've always had people who loved you by your side. Your parents and sisters were fully accepting of your choices, and they loved you. Everypony you meet instantly becomes your friend. But take someone like Trixie. She isn't truly evil, but she can be a pretty big bully at times. She doesn't seem to have many friends or people she can rely on beside herself, especially since she travels all the time. That loneliness makes her bitter." Another example came to mind and Twilight smiled. "Now take Tirek. He was raised learning that if he wanted something, he had to take it by force. He had a brother who betrayed him at one of the most crucial moments of his life. Look at him now, a being of rage and hate, forever trapped in Tartarus."
Pinkie mulled this new information over for a moment. "Ok, sure, it makes sense. But what does this have to do with the pond Twilight?" she asked, still missing the crucial part of the explanation.
"Yes, right." Twilight said, blowing a strand of hair from her mane out of her face. "I believe that the pond has some sort of magical quality to it that actually splits a ponies potential. Maybe not down the middle, but it tears off a chunk of what makes that pony whole in order to make the copy. The only reason all of your clones were so happy and good natured, albeit a bit mischievous, was because you have such a high potential for good. That's why you felt less and less happy with every copy that was made, they were literally sucking all the good out of you and leaving only a depressed husk." Twilight took a deep breath as she finished her rant of an explanation.
A silence passed over the two ponies as they each mulled over the new information they had learned today. But, finally, Pinkie spoke up.
"Ok, so, now what?" she asked.
Twilight stood up and began walking to the door, which she opened with her magic. "Now, I plan on getting some rest. It's been a long day and I'm going to need it if I'm going to be running tests tomorrow."
"What kind of tests?" Pinkie asked as she followed her friend out of the room, watching as Twilight used her magic to not only close the door but make it disappear as well.
"I'm going to the pond to run tests in order to find out what gives the water it's magic quality." she paused and turned to Pinkie. "Can you do me a favor and not mention this, or my lab, to any of the girls or Spike? I really don't need them running amok in there." she asked.
Pinkie held a hoof up and did an all too familiar motion. "Cross my heart and hope to fly, stick a cupcake in my eye." she chanted the familiar words of a Pinkie Promise and winked at Twilight.
"Thanks Pinkie. Now, let's get something to eat, I'm starving!" Twilight said as she made her way up the stairs, listening as Pinkie listed off the specials Sugar Cube Corner had today.