Fluttershy shivered in the medbay. "Oh, it was awful! She even tried t-to tell me something. If I had just come sooner..."

Twilight put a hoof on Fluttershy's shoulder. "It's okay...I think I preserved her in time, so she's not dead yet, and I've got a plan..." She stared down at Rainbow's petrified head, which had a tongue sticking out and a derped expression.

Spike meanwhile was busy tinkering with a lavender crystal platform, similar to the cutie map's, on a golden stand atop a large brain-like grey crystal, in a box.

Everypony else sat on medbeds facing the three. AJ was covering her head with her hat, while leaning against Rarity. Pinkie's hair was fully deflated as she stared at a wall while slowly crying.

Twilight sucked on her own lips a moment. "...I know this is going to be hard for all of us, but let's just be calm and rational." She put up some notes on the medbay wall. "The stuff covering where Dash's midsection and neck were cut, as well as her waste exits, is clearly changeling goop. The only logical reason for it to be all of those places is to prevent any blood or waste from leaving evidence behind."

Rarity patted AJ before hopping up off the medbed. "Hmm, so Ocellus hasn't gone feral. She's still able to plan"

Twilight tapped her chin with her hoof. "Not necessarily... You see, I have a spell that detects changelings. Impractical to cast continuously, but I made sure to use it a bit earlier, and...it only showed me traces in the rock that came off us when we woke up, and some residue in the toilet system. The spell ignores inorganic matter, so..."

Rarity gasped. "She's...she's become a parasite in one of us? That's ghastly."

Pinkie jumped up. "There's an impostor among us!" She then sat back down and rocked back and forth rather violently while a tear rolled down her cheek.

Twilight nodded solemnly. "That's correct, and for all we know, Ocellus isn't even conscious, and just acting on instinct while whichever pony she's in figures out how to accomplish things. Now, I don't know how Rainbow calling her 'Lightning' fits into all this just yet, but my best guess is whoever was controlled either let Ocellus out for a bit, or was enveloped by her, to take the form of Lightning Dust to catch Rainbow off-guard. I know one way to find out for sure...we ask Rainbow."

AJ huffed as she threw her hat down to the floor, and wiped her eyes. "And how the hay ya expect to do that, sugarcube?"

Twilight cleared her throat as she gestured towards Spike. "Ready?"

Spike blew a bit of dragonfire on a part of the golden stand and saluted. "I think so, but this seems...wrong."

Twilight groaned. "Wrong is a pony being killed for no good reason. I don't know how much this will undo, but...I have to try. Now stand back everypony, this is gonna get weird. First, gotta undo this..." She lit her horn and zapped Rainbow's head, which unpetrified. "And bring it back to life for a moment..." Another zap left Rainbow's eyes and tongue moving, making Rarity whine.

Pinkie swooped in and held up Rainbow the head. "Hey Dashie, you really got ahead in life! You're way more aerodynamic now! Ahahah. Ooh, and the monster didn't want some Rumpbow Desert to go with its wings, foreleg fries, and shoulder shake! Haha." Pinkie shook a bit as she smooched Rainbow sloppily.

Rainbow's eyes went wide, and blinked a few times.

Twilight rubbed her temples. "I suppose that's one way to keep Dash conscious...now...one max power mindflayer spell..." She shot an intense pink beam into Rainbow's head. "Then a linking spell, a come-to-life spell on the crystal..." She hit some magic onto the brain-like crystal. "...then a project form spell with some custom scripting..." She shot a blue beam into the box, and suddenly it formed a hologram of Rainbow as the crystal turned brain-pink.

Rainbow's head suddenly glowed brightly, then poofed into magic sparkles.

Pinkie was left with her eyes spinning around and spiky hair. She burped. "Mm, that tongue was like spicy skittles!"

The hologram blinked, gasped for air, then smacked its lips. "Mmm, bubblegum Ponk!" She looked at her hoof. "Ooh, glowy..."

Pinkie gasped loudly. "Rainbow's a ghost! Is she gonna fly through walls and possess us now?"

Twilight rolled her eyes as she levitated Rainbow's rear into a storage locker nearby. "Not exactly. I've copied her mind from her brain into this setup based on the Cutie Map to give her a sort of second life. Unfortunately...her brain degraded a fair bit, from what I saw in the mind copy...so I don't think all her wits are there."

Holo-Dash picked her nose. "What's a wit?"

Applejack slowly took her hat off. "S-sugarcube? Ya alright? Ya know my name?"

Holo-Dash giggled. "Uh duh! You're Applejerk, my fave pony to compete with! Ooh, how fast can I go as a box ghost?"

Applejack put on a puzzled expression and hugged Rarity. "Good enough for me..."

Twilight cocked an eyebrow. "Unfortunately, the projection area is pretty small, and the crystals are too fragile to be moving around, so you're stuck where you are. Anyways, um, do you remember what happened? I tried to peek myself, but your memories are a mess, no offense."

Holo-Dash flew a bit, bouncing around a sort of invisible box barely three ponies wide and four tall, then crossed her forelegs, huffed, and nodded. "Horseapples. Okay, fine...first I checked the soda and snacks, then I went around burpin' up a storm, then I went to have some fun playing giggles and grab-apples, but Rarity was a fuddy-duddy, and AJ was a bad sport, even though it's one of her favorite sports! So then I went to make sure the ship was all vroom vroom, but then uh...the yellow uh, Buttershy, was there, and she hates going fast, but then Lightning Dude was there, and she...wanted faster, and...uh...she did a sick move with some kind of blade on her wing!"

Twilight, Rarity, and Spike all stared at Fluttershy.

Fluttershy blinked. "Uh, Rainbow, my name is Fluttershy, and I uh...I wasn't in the room until after that uh, 'sick trick'."

Holo-Dash shrugged. "Well sorry, but that's how I remember it, Flittershy. You were actin' all sorts of suspace, susfishuh, uh...sussy! Actin' sussy!"

Pinkie's eye twitched. "Fluttershy..."

Fluttershy eeped and hid her face with her wings.

Twilight stepped in between them. "Whoa whoa whoa, before any accusations get thrown around based on half a pony's memories, let's take stock of everypony's story. I'll use a spell to record memories onto a book, so we can all check them."

Pinkie crossed her hooves. "Okay, but I'm telling you, first it was Gerald the spider, then it was Rainbow, that butter coat hides a greasy changeling!"

Twilight cleared her throat. "Conspiracy theories aside, Spike and Rarity, you two go first. You were the only ones I didn't see after we unpetrified."

Rarity's eyes went wide. "Uh, well darling, m-most of our time together was rather private you see. After a bit in the little mare's room, and s-some time to ourselves, not much really happened except for a brief encounter with the others."

Spike walked over in front of her. "Sorry Rarity, but this is too serious to be so vague. So...Rarity has a bit of a sensitive stomach, and the petrification just really messed up her whole digestive system."

Pinkie giggled. "He means Rarity had the trots. Like, the screamin' trots. It was like Mount Vehoovius eruptin' in there."

Holo-Dash snickered.

Spike cleared his throat. "Anyways, once I had her all cleaned up, she wasn't exactly feeling alright, so we went to the medbay and, well, she wanted to reward me while doing something that would make her feel good too, so...we kissed here instead of doing our tasks." Spike gritted his teeth as he locked eyes with Twilight. "Uh, and then the alarm sounded, and I noticed Rarity had left while I took a nap."

Twilight stood with her jaw wide open, and glanced down at the book, then to Rarity, staring with a scowl. "Rarity, I'll spare you the third degree for now while we deal with all this, but I want your assurance that if you're going to actually reciprocate my little brother's romantic advances, you're treating him less like a servant and more like an equal, and understanding that he has trouble saying no to a mare, especially one twice his age."

Rarity nervously chuckled. "Y-yes of course, you have my word, darling! Consensuality is paramount, and I would never dream of hurting Spike."

Twilight gave a clearly-fake smile. "Excellent. Now, think of the same events so I can check they match."

Rarity closed her eyes and concentrated. "Okay...so after my alone time with Spike, I had to freshen up and get decent, and had the misfortune of meeting Pinkie, who seemed to think it appropriate to interfere with my hygiene, and...you got all you needed to know from when I encountered Fluttershy, darling." She shuddered. "So I went to clear my head by gazing down at the lovely planet Marēs..."

Holo-Dash piped up. "I told her part of it looked like poo, heh."

Rarity scoffed. "Thankfully when Rainbow's shenanigans came to ruin the moment, AJ was there to put her in her place, even if in a rather uncouth manner. Anyways, a bit later when I went back to check on Spike, and that's when the alarm sounded, as you know when I met you in the bathroom, darling."

Twilight. "Okay..." She looked to Applejack. "So...you seem quite central to this, what's your story?"

Applejack stared a moment at Holo-Dash, then took a deep breath. "Well, I was doin' my tasks just like ya asked. No fussin', no wastin' time lovin', and no drama. Just had to stop to pee and had a task to make sure the toilets were doin' alright anyways, and met up with Fluttershy an' Pinkie. After that, I went to make sure the algae was growin' right for our oxygen, but Pinkie kept talkin' that nonsense about funerals for our eight-legged pest-eaters, and Dash was slackin' off with horseplay, and Rarity was slackin' off stargazin'. I was ready to blow...and that's when Rainbow made the mistake of testin' me with a wing to my rump, so I returned the favor by makin' her rear red as an apple ready for harvest and leavin' her a flanksore loser, just like Fluttershy an' Rarity said. Pinkie thankfully had a lick of work ethic, so me and her went to electrical to get comms workin', but before we could fix it, the alarm sounded."

Twilight turned to Holo-Dash. "Well?"

Holo-Dash shrugged. "Nuh-uh, Rearity was the one who was flanksore! She begged me not to touch her flank. Somethin' about Pinkie makin' it sore when she was tryin' to make it unsore. And how I'd mess up her precious cutie mark makup! Bawk bawk, scaredy little chicken Rarity! Sussy bawk-a!"

Rarity snorted. "Call me what you will, I refuse to partake in such childish games. Now Twilight, must we listen to this half-Rainbow's prattling on? The uncouthness I can handle, but she has no respect either!"

Twilight sighed. "Rarity, it's her murder, it's only right we let her give her side of it, and you know even half a mind might have vital clues, even if they're buried. Now...Pinkie?"

Pinkie sat with her forelegs crossed. "Well first I zipped to grab my task list and get some snacks, but I ate too fast or somethin' and went to throw up in the bathroom, and boy Rarity and Spike were a tough crowd in there, so I went back to eating snacks I could keep down, but my tasks still made no sense, and I went back to the bathroom to wash up my sticky hooves, and then I saw Rarity struggling to really push a pedal properly, and helped her, but I kinda helped too much and she became like a pony-shaped water balloon, and then when she deflated, she beat me up! And Fluttershy was there too, then AJ, and they were way more fun! We went to do our tasks, then I found Fluttershy all sad about a spider by oxygen, so I began trying to explain to AJ the importance of a spider funeral, and then I saw Rarity at the big window, who would absolutely understand the plight of poor Gerald even if she is no fun, but then I got to see AJ use her HOOVES OF STEEL on Rainbow, and AJ insisted we needed to go fix comms so I could tell Maud all about the rocks in space, and I was all 'oh these two pink wires must connect', and I really got in the groove. Soon, I was shakin' my groove thing to the beat of the music with my whole front stuck in a panel and...well then Applejack slapped my groove thing's party pudge silly and told me that wasn't music, it was an alarm! So I popped in a vent and right out here!"

Spike cocked an eyebrow. "Popped in a vent? Those aren't supposed to be wide enough for ponies, especially ones with 'groove things' the size of yours!"

Twilight put a hoof on Spike's shoulder. "It's Pinkie... And that all lines up." She stared at the book. "Hmm, some incidental memories have been showing up, but...all clearly show you to be yourselves. Whoever's got Ocellus inside them must be deeply controlled or even unaware. Rarity, can you look over the book while I recount my perspective?"

Rarity nodded and took it.

Twilight shrugged. "It really wasn't eventful. As you know from Fluttershy, I had her go deal with her constipation, then I spent a while sorting through messages until Rainbow swung by to belch the alphabet, not listening to a word I said about Ocellus and a possible intruder. I'm pretty sure at this point that her brain had a particularly bad reaction to the petrification... Well anyways, then Fluttershy came to actually listen, and I had her check up on Rainbow, while I went to find Spike. I took a pit stop in the bathroom, which turned out to be a huge mistake, as you all caught me with my tail up with an urgent need to cast a spell before I was even done."

Rarity examined the book carefully and sighed. "Yes, quite uncouth, darling, and...you seem to check out too. That leaves only really two ponies of interest...myself, and Fluttershy."

Author's Note

Claimed location timeline:
1 (First tasks):
-------------Storage 1==*==33Medbay==Bathroom2-X-Observation
-----------------||-----------------------X----------------||-------------------||
Engines=Hallway==*=======Kitchen1====Bunks======Oxygen==Cockpit
-----------------||--------------------------X---------------||-----------------||
-------------Storage 2===*===Electrical==Admin2=====Comms1

2 (Sparity):
-------------Storage 1==*==Medbay==Bathroom-X-Observation
-----------------||-----------------------X----------------||-------------------||
Engines=Hallway==*====Kitchen====Bunks======Oxygen==Cockpit
-----------------||--------------------------X---------------||-----------------||
-------------Storage 2===*===Electrical==Admin======Comms

3 (Spike falls asleep):
-------------Storage 1==*==Medbay==Bathroom12-X-Observation
-----------------||-----------------------X----------------||-------------------|2|
Engines=Hallway==*====Kitchen====1Bunks======Oxygen==Cockpit
-----------------||--------------------------X---------------||-----------------||
-------------Storage 2===*===Electrical==Admin======Comms

4 (Rainbow the troublemaker):
-------------Storage 1==*==Medbay==Bathroom-X-Observation
-----------------||-----------------------X----------------||-------------------||
Engines=Hallway==*====Kitchen====Bunks======Oxygen==Cockpit
-----------------||--------------------------X---------------||-----------------||
-------------Storage 2===*===Electrical==Admin======Comms

5 (Alarm):
-------------Storage 1==*==Medbay==Bathroom-X-Observation
-----------------||-----------------------X----------------||-------------------||
Engines=Hallway==*====Kitchen====Bunks======Oxygen==Cockpit
-----------------||--------------------------X---------------||-----------------||
-------------Storage 2=*==Electrical==Admin====Comms