Pinkie Pie was many things to Twilight. Overly excitable, loud, a ray of sunshine, a great friend, and the list can go on for ages, and would be alphabetized if a physical list existed. She had seen the pink pony do all sorts of bizarre things be it for fun or out of seriousness. Not only did she possess some manner of psychic powers that predicted the future using her body's physical actions, but she even had a party planning lair and detect whenever promises were broken. Truly, the mare was a mystery to her.
But lately, it seemed like Pinkie Pie had been much more bizarre than her usual normal. It all started about a month ago as far as she could tell. The six of them had scheduled a lunch party for a Monday they had all set aside for each other. Everything looked promising at the start; everypony knew what they were bringing, the last friendship problem had been a couple days before, and Starlight was tending to anything that came up. Everything was perfectly set up... until Pinkie Pie didn't show up on time.
That had been a point of worry for all of them. As the one who did a majority of the planning for this lunch, they had expected her to be at the castle before any of the other guests. Instead, she showed up 30 minutes late, something unheard of for the pink Earth Pony whenever her friends were involved. At first, they simply assumed she had something to attend to with the twins or the bakery. After five minutes, however, they quickly realized something was amiss with their friend.
When she did arrive, they had been about to go out searching for her. Naturally, she was quick to apologize and provide an explanation. The fact that she was smiling confused them until she told them just why it took so long for her to arrive. "A new friend came to Ponyville?" Twilight was certain Pinkie would in fact be derailed by somepony new coming to town. A quick glance to Applejack confirmed that she was in fact telling the truth, but something still bothered her.
"We~~~ll... not exactly 'came to Ponyville'..." She never lost her smile or enthusiasm. "You see, this new friend of mine said they want to visit, but they need some time until they can come here!"
"I'm sorry, darling, but how exactly could they talk to you without coming to Ponyville?" Twilight was grateful Rarity was there to ask the question she herself was pondering. "After all, it's not exactly possible unless you weren't here in Ponyville yourself."
"Oh, I never left Ponyville, silly filly!" She rolled her eyes as if she were stating the most obvious thing. "My new friend spoke to me through Madame Pinkie's crystal ball!"
The silence following the statement was practically deafening. Twilight was almost expecting Pinkie Pie to burst into laughter and say she was joking. Much to her growing concern, no such change occurred. Instead, the pink mare kept smiling as if it were perfectly normal to say somepony spoke through crystal balls. The young alicorn shared nervous looks with her other friends as Pinkie Pie stood there as if nothing were wrong.
"Um... Pinkie are you sure about that?" To say Twilight was shocked that Fluttershy raised the concern would be a reasonable understatement. If anything, she expected the butter yellow pegasus to passively not commit to agreeing with her. "Are you sure it's not Discord simply pulling a prank on you or something?"
She shook her head. "Nope! Couldn't be Discord. My new friend called him a pest when I asked if he was Discord!"
"Well, do ya think you could get your- er, I mean, Madame Pinkie's crystal ball so we can meet this uh... friend of yours?" Bless Applejack and her straightforward, logic-grounded ways of thinking! If there was a way to prove Pinkie's claim, then the easiest way to do so was to just try speaking with her friend themselves.
"Oh I wish I could!" she chirped. "But my new friend only had so much time and I couldn't move the crystal ball without breaking the connection." Connection? Limited time? This all sounded far too convenient to Twilight.
"Say, Pinkie?" The pony turned her attention to Twilight, her eyes still shining with happiness. "Why don't you at least go get the crystal ball so I can take a look at it? Maybe I can figure out where your new friend is."
She gasped as dramatically as she usually did. "That's a great idea, Twilight! Then I can throw him a party sooner!" She quickly ran off through the door as nothing more than a pink blur.
"Twi, are you serious about this?"
"Not at all, Applejack." She shook her head, trying to keep any possible jokes out of mind. "I'm positive that if there's anything up with that crystal ball, then it's probably somepony playing a prank. The only other thing I can think of is something that's a little out there, maybe even for Pinkie Pie."
The other four shared looks of confusion or concern before turning back to the Princess, with Rarity pushing for information. "And that is...?"
"I think Pinkie Pie might have made an imaginary friend." Nothing but silence met her statement, they wanted to deny it, but it made a lot of sense. "The only other thing I can think of is if she somehow made contact with someone from Sunset Shimmer's world, but the mention of Discord disqualifies that option."
Unfortunately, the crystal ball was a bust. It didn't matter what spells Twilight, Starlight, Sunburst, and even (unfortunately) Trixie threw at it, none of them could figure out just what Pinkie Pie said she was talking to. As far as their magic could tell, it was just a regular crystal ball with nothing spectacular about it. After the unsuccessful examination, the only plausible theory left was that Pinkie Pie, for some reason, decided to make herself an imaginary friend, so they let it be. After all, what harm was it for Pinkie to have somepony to keep her company when she got too bored?
From there, things seemed relatively normal. For the next few days, Pinkie Pie seemed to keep up her regular routine, except for the fact that she apparently set aside half an hour for her imaginary friend in the crystal ball. Twilight tried checking with the Cakes about her friend's well-being only to receive reassurances that, crystal ball aside, she was perfectly fine. Sure, she didn't like it, but Twilight was willing to just let Pinkie Pie go on with her new hobby. It seemed like it was largely harmless; just Pinkie being Pinkie.
Until she saw it herself.
She didn't know when it started, whether it was just that day or the day before, but roughly a week after the lunch incident, Pinkie Pie had started carrying the crystal ball around with her in public. The large ball, which still looked as normal as it ever did, was lodged in Pinkie Pie's tail as she walked around Ponyville and went about her day. On its own, that would have been harmless, if a little eccentric. But when Twilight could see Pinkie seeming to listen to it before talking to it, she knew she had to step in but... Pinkie had conversation with inanimate objects all the time... right?
She had been getting worse over the last week. From what the other ponies in town had been telling her, Pinkie Pie was becoming almost manic rather than quirky. She openly spoke with her crystal ball as if it were another pony and not a large chunk of glass shaped into a sphere. More concerning was her attitude towards actual ponies who tried engaging her. Whereas before, she would often stop her entire day to have a conversation with anypony who said 'Hello' to her, now she would often ignore those ponies or glare at them distrustingly. The only one to get one of her smiles was that crystal ball.
Twilight would have noticed sooner, but she had been busy trying to help Fluttershy with a problem concerning the animals that lived near her home. According to her, several rabbits, squirrels, and a couple birds had inexplicably gone missing. Normally, she would have assumed they were moving around or finding new homes, but the other animals were becoming terrified, something that, in her experience, meant something was making them disappear. The animal caretaker had then enlisted her and Applejack to try figuring out not only what was making animals disappear, but also how to protect the animals still there.
Unfortunately for the pegasus, they had been unsuccessful as no animals went missing while the three of them had been building traps. Once they had decided whatever was responsible was gone, it started up again but at a much slower pace. They had been so busy, she hadn't known what Pinkie Pie's condition was like until Starlight Glimmer and Rainbow Dash came to her with their concerns. The two had tried convincing Pinkie to come spend some time with them and hopefully get her away from that crystal ball for any amount of time.
Whereas before she would have jumped at the idea of spending time with her friends, this new Pinkie Pie angrily told them off in words nopony assumed she would even know. She then ran off, denouncing them as her friends and saying that the only one who understood her was the friend she had made in her crystal ball.
Twilight was sick of this. Enough was enough. It was high time they addressed Pinkie Pie and this... "friend" of hers. Gathering the other four members of their group and Starlight, the group of six made their way into Ponyville with their sights on Sugarcube Corner. Unlike their usual gatherings, the atmosphere was somber around them as they marched to their friend's home. The weather was not helping the situation as the sky was filled with grey clouds that cast the town in a gloomy half light. It was in this depressing atmosphere as they walked that she thought back on the last month and all the warning signs she should have seen in her friend. She should have done something sooner.
Upon arriving at the bakery, the mares saw that several of the windows on the third floor were boarded up but were allowing a suspicious orange light through the cracks. The sight of such a thing was a huge red flag for Twilight, who knew that the boards were all on windows that looked into Pinkie Pie's room. With a quick reassurance to the other mares, she lead the way into the bakery.
Inside, Mrs. Cake was doing her best to ignore whatever was happening upstairs. Her husband, Mr. Cake, and their foals, Pound and Pumpkin, were nowhere in sight. "Oh, Princess Twilight! And everypony else! You girls are just in time." The older mare looked very relieved at the sight of the six ponies, as though a weight were lifted from her shoulders. "Pinkie has been holed up in room for almost an hour now after running in here with that crystal ball of hers."
"Mrs. Cake, where are your husband and the foals?" In Pinkie Pie's current state of complete unpredictable behavior, there was no telling what she would do to the stallion or babies.
"Carrot took the little ones out for a quick walk when Pinkie came home." Perfect, that just meant there would be fewer ponies that may get caught in the crossfire between the friends if things went south.
"Mrs. Cake, I'd like to ask that you go outside for a little bit. We're going to try getting her out of here and getting rid of that crystal ball," she explained. Twilight made sure to keep her voice low to avoid Pinkie Pie potentially over-hearing them. "There's no telling how violent she'll get when we try to do so."
Getting a resigned agreement from the mare before she walked out the door, Twilight gave a solemn look to her friends. Without saying a word, the six friends shared a silent agreement that this was necessary. With the princess leading the way, the six ponies steadily made their way up the stairs, each step creating a feeling that a great weight was bearing down on them, as if to discourage them. When they arrived at the pink pony's door, they found it locked with orange light being barely visible under the door. In the silence that followed them, Twilight could faintly hear soft murmuring on the other side of the door.
Steeling her resolve, Twilight slammed her hoof on the door. "Pinkie Pie, it's us!" Her calls brought the murmurs to an abrupt halt. "Open this door. We need to talk." No response.
"Um... Maybe she isn't in?"
Rarity shook her head as Twilight resumed pounding on the door trying to get Pinkie's attention. "Don't forget, Mrs. Cake said Pinkie came up here and never left, and the windows to her room are all boarded up from the outside, meaning she couldn't get out, darling."
"Oh, she's in there. We just need to get her out." Rainbow Dash flew over the group and slammed her front hooves into the door. "Pinkie, open the damn door! It's us, your friends!"
When nothing but silence replied to their efforts, Applejack pushed her way to the front. "Pinkie, if ya'll don't open the door by the count of three, Ah'm bucking it down!" No response. "One... two..." She got into position, tensing her muscles in preparation to kick the door down. "THREE!"
The door abruptly opened before Applejack could raise her legs. "Hi, everypony!" Pinkie Pie was standing before them, and her appearance was the most concerning part of the entire situation. Her mane and tail, normally poofed up and curly like cotton candy, now hung completely flat. Despite the sign of her sadness, she wore a twisted, perverse form of the reassuring smile they knew her for. Instead of warmth and love, it was filled with madness and sent shivers down all of their spines. "How can I help you girls?"
Twilight quickly took lead as she presented Pinkie with their primary reason for coming here. "Oh, you're here because of him? That's wonderful!" Her smile took on a more dangerous edge. "After all, I wanted you all to meet him when he got here, and this makes it so much easier on me!" She quickly spun around before asking them to follow her up the stairs into her room.
Before Twilight could move, Applejack put a foreleg in front of her to make her stop. Twilight, confused, followed her friend's line of sight and felt nauseous at what she saw. Hoofprints. Pinkie's hoofprints. Her bloody hoofprints. Whatever their friend had gotten into, her tracking blood was not a good sign. Avoiding the tracks as best they could, the group ascended the rest of the way into Pinkie Pie's room ready to bolt at a moment's notice. As they made the short trek, the light was quickly revealed to be a series of candles set up in regularly spaced intervals to create as much light as possible.
The room itself was something out of somepony's darkest, most depraved nightmares. Large, circular patterns, filled with alien, unintelligible writing dominated the floor. The dark color of the writing and markings left no doubt in Twilight's mind that they were drawn in the blood that clung to Pinkie Pie's hooves. She could hear Fluttershy silently sobbing and repressing her desire to vomit behind her at the room's new centerpiece.
The center of the circles was adorned with a makeshift altar decorated with the mangled and desecrated corpses of small animals, presumably the ones that had gone missing in recent weeks. In the center of the altar, resting on a small dais of still bloody bones, sat the crystal ball. The damnable object that started this entire fiasco. For reasons beyond her understanding, the once clear object was now pitch black, as though it were filled with darkness.
"I'm so super duper sorry I've been such a Grumpy Pie lately." The cheerful tone in her voice betrayed the macabre scene surrounding them as she stood besides that wretched altar. "I've just been trying to make everything juuuust perfect for my friend to come here to Ponyville so everypony can meet him!"
"Pinkie this needs to stop!" Twilight was desperately hoping they could talk some sense into her and wouldn't have to resort to anything that could hurt their friend. "There is nopony in that crystal ball, nopony is talking to you through it, and you need serious help!
Her smile faltered. "What? N-no! I know he's real! He can tell you!" She was looking at the crystal ball with a desperate, manic smile on her face. "Come on, show them! Tell everypony you're real!" The ball gave no answer to her demands. "It's ok, don't be shy! Please... just say something..." She was silent for a moment, staring into its empty depths. "Why won't you... unless..."
"That does it!" Rainbow Dash zoomed across the room Grabbing the ball in her hooves and yanking it from the altar. "This stupid ball has caused way too many problems. I'm sick of it! I WANT MY FRIEND BACK!"
Twilight took a quick look at Pinkie Pie and didn't see any fear. Instead, she saw a hopeful look on her face. A look of relief and... joy? Her stomach dropped as she realized why Pinkie wasn't stopping Rainbow Dash. "Rainbow, WAIT!"
"Starlight, now!" She threw the crystal ball with all her might, leaving Twilight unable to stop her or Starlight Glimmer as the mentioned unicorn shot a beam of energy through the crystal ball, shattering it into pieces. The shards flew all over the place, hitting the ground with a soft tinkling. Inexplicably, the pitch black coloring faded from the shards once they stopped moving.
"Thank you..." Pinkie Pie's whisper was barely audible despite the silence that hung over you. "I never realized it, but this was the last thing I needed to do." The candles' light seemed to dim as screams were heard outside. The little bits of sky visible through the holes in the windows darkened dramatically. "But thanks to you girls, my friend is here in Ponyville..."
The smile on her face was absolutely demented, now threatening to split her face apart as her eyes unfocused. "LET'S GO WELCOME HIM TO EQUESTRIA!"