If you cut an alicorn, does she bleed?
Rainbow Dash saw it happen.
The Ursa Major rampaged toward Ponyville, trees crushed in its wake. Applejack and Pinkie Pie galloped alongside, tossing boulders and bucking at its flanks. Fluttershy zipped ahead, evacuating helpless creatures from destruction. Rarity dazzled and distracted the beast with spells.
Rainbow herself flew interference, knocking down any hurled debris before they could damage the outlying buildings. Their combined efforts slowed, but didn't stop the creature. She wondered when help would arrive.
She barely deflected a spinning tree branch, then heard the pop of teleportation magic behind her in the sky. Momentarily distracted, she glanced over her shoulder, away from the battle.
"I came as fast as I could!" Twilight Sparkle yelled over the Ursa's roar. Dust and cloud swirled in the wake of her oversized wings. "What's the situ—"
Rainbow could only watch as a boulder the size of a wagon hurtled past her shoulder and hit Twilight with a wet crunch.
The sound echoed through the sky, distinct enough that everypony glanced upward. Even the Ursa Major paused in surprise.
The boulder continued in a lazy arc and landed a quarter mile away, plowing a dirt trench forty strides long before grinding to a halt. With the crystal clarity of her flier's vision, Rainbow thought she could see the hint of a red and purple wingtip underneath it.
Why was it red?
Somepony screamed. The Ursa Major snorted, and set its sights on the nearest outlying cottage.
"Twilight!" Rainbow pumped her wings toward the ground. At the edge of her rapidly tunneling vision she saw her other friends racing toward the crash site, but she was the fastest. She slammed into the dirt and skidded to a halt. "No no no, Twilight!"
Pinkie Pie caught up, somehow ahead of the others. "Where is she!?"
"Under!" Rainbow cried, pulling at tons of unyielding stone. "Help me! You have to break it!"
Pinkie's face contorted, sick. "Okay, hang on!" she shouted. She ran a hoof down a seam in the rock, tapped twice, reared back in a martial arts striking pose, and—
Lavender magic suffused the stone, and Pinkie and Rainbow stumbled away in surprise. Dirt and gravel shifted. The stone shuddered. Then it levitated upwards.
Beneath, Twilight stood on her own four hooves, surrounded by a glowing magical shield.
"Not… very… nice!" she strained. Then she flicked her horn, and the boulder zipped back into the sky. With an almost comical thump, it bounced off the Ursa Major's jaw and shattered.
The leviathan magical bear grunted and sat back on its haunches, stunned.
"Fluttershy!" Twilight shouted. "Now's your chance!"
Slower than the others and distracted by helping various animals, Fluttershy had been at the back of the pack. She nodded and reversed course, zipping toward the Ursa. If anypony could calm a raging monster in a moment of surprise, it was her.
But Rainbow paid no heed. She just stood, jaw agape as the rest of her friends galloped out of the trees and into the divot left by the boulder.
Applejack gasped in relief. "Land sakes Twilight, y'all gave us a mighty scare!"
"Oh goodness, I'm so glad to see you're okay darling," Rarity said, trying desperately to catch her breath without looking like she'd been in a blind panic just seconds before. "We thought you'd… well I don't even want to say it!"
"Me too," Twilight replied sheepishly. "Luckily I got my shield spell up just in time, otherwise it could have been a lot worse."
"I'll say," Pinkie agreed. She examined part of the boulder, sheered away on impact. "Solid granite! I would've had to break it off in chunks to get you out."
In the distance, the Ursa Major roared defeatedly and trudged toward the Everfree forest under Fluttershy's withering glare.
Twilight breathed a sigh of relief. "Well, looks like that problem's been solved. Now I've got to deal with all the paperwork that comes with damage to a nature preserve, reassure the Mayor and townsponies that they're safe and the princesses care about them, not to mention…"
Her voice trailed off as she trotted toward the village. Pinkie, Applejack, Fluttershy, and Rarity followed.
They were all too distracted with relief to notice that Rainbow was still standing aghast in the crater, staring at the back of Twilight's head.
Rainbow hadn't imagined it. She kept playing the scene over and over again in her head: Feeling the wake of the boulder past her feathers. Seeing it crash into Twilight's face. Hearing the sound of stone against flesh.
Like stomping on a bundle of soggy celery.
She hadn't seen even the slightest hint of magic. Not a single glimmer of the shield or levitation spells Twilight conjured so many times before.
And yet.
"Look, I'm not saying you imagined it, Rainbow," Pinkie Pie said, zipping across the kitchen. A cloud of displaced flour whorled in the air behind her. "But even alicorns don't take a boulder to the face and trot away unharmed unless magic is involved." Her tail twitched spastically.
"I know what I saw," Rainbow said. "It was clear as day, it happened right in front of my face!" She sighed and rubbed her eyes. "I can't stop seeing it. Over and over. Hearing it."
Crunch.
She started, but it was just Pinkie cracking three eggs into the mixing bowl. At the same time. Somehow.
"Have you talked to Twilight about it?"
"No. She'd just say 'well Rainbow Dash, logically speaking since I'm standing here then obviously I got my shield up in time, something something quad eros ergo yada yada yada' and it'd all make perfect sense."
"Well, she is pretty good at making those logical points," Pinkie said. She mixed thoughtfully for a moment, then put the bowl down. "On the other hoof—" she smoothly turned and caught a jar falling from the top shelf before it could shatter on the floor "—what's the harm in asking? Even Twilight will admit there's no explanation for some things. Maybe it's like some subconscious alicorn defense mechanism or something."
"I suppose so…" Rainbow pushed around the half-eaten cupcake in front of her. Out of obligation more than desire she finished it off, but even Pinkie Pie's divine baked goods couldn't lift the gnawing pit in her stomach.
Rainbow Dash spent the next several days discreetly observing Twilight Sparkle.
It wasn't hard, really. They were friends after all. If Twilight ever spotted her, Rainbow would wave and smile. Sometimes she'd pretend to be on an errand in the opposite direction. Sometimes she'd trot over and have a friendly chat.
But her efforts were in vain. Not much happened in Ponyville in an average month, certainly not anything exceptionally dangerous, like an Ursa Major attack.
Plus, Twilight was an alicorn princess. Since growing out of an awkward phase with her new wings, she'd become ever more coordinated and graceful. She deftly skirted even the most minor obstacles, and her peerless command of magic precluded even the opportunity of a papercut.
By the end of two weeks, Rainbow was downright bored.
The horror of the boulder incident faded into desensitization, the memory growing mundane as she replayed it over and over. She wasn't sure anymore if she'd seen any magic barrier.
But the sound remained.
She was almost prepared to let it go. Idly she followed Twilight into the market, wearing a set of saddlebags for plausible deniability. It was a reasonable cover; Rainbow actually did need groceries. Her icebox was running low on fresh vegetables, and her pantry was frighteningly bare of high-energy snacks
Out of the corner of her eye she watched Twilight wander into the apothecary, probably for spell components. Across the street, Rainbow busied herself comparing prices on apples and celery.
A loud crash sounded next to her.
Snapping her head around, she immediately saw the source: A guilty-looking pair of foals next to a tilted shelf of glass jars.
"Now look what you've done!" a harried-looking pegasus mare shouted. "I told you to stop rough-housing! No! Don't move, you'll step on something!"
The mare alternated between scolding her foals and apologizing to the shopkeeper earth pony, who assured her it was all right as he grabbed a broom and swept glass into a dustbin.
With nothing better to do, Rainbow flitted over. One of the foals was standing frozen in a pile of glass, a partly shattered jar next to his hooves.
"Here buddy, lemme help you out." She gently hovered over the foal and lifted him off the boardwalk to a safe portion of the street.
"Thank you so much," the mother said. Her mane was frazzled and her eyes bore dark circles. "Swear to Celestia, can't take these two anywhere."
"No trouble ma'am," Rainbow replied with a slight bow. "Happy to help."
"Everything okay out here?"
Rainbow turned. Twilight trotted toward them out of the apothecary. Rainbow opened her mouth to reply—
—just as the soft part of Twilight's hoof came down on an ugly shard of broken jar.
"OW!" Twilight stumbled forward and crumpled onto the packed earth.
A surge of excitement, then clammy horror washed over Rainbow as she realized the morbid reality of what she'd so eagerly awaited. Her friend was hurt, and it was exactly what she wanted.
The shopkeeper rushed forward. "Princess Twilight! Are you okay!? Hold still, hold still, let me have a look..."
"No no, I'm okay," Twilight said. She pushed him away and stood, then shook out her leg and turned her hoof upward. "See? Didn't even break skin."
Relief flooded into Rainbow even as her jaw fell in astonishment. "But… how…?" She scoured the street for the piece of glass.
"I saw it at the last second and pulled my hoof up," Twilight said. Her magic flashed and the jagged shard levitated in front of her. "Barely pricked me, thank goodness! That could have been bad."
"Just glad you're okay Princess," the shopkeeper said, holding out his dustpan. "Had enough accidents already."
"Hopefully no more," Twilight replied as she deposited the shard. She turned to Rainbow. "Well that's enough excitement for one day I think. I still have an hour before I need to meet the town council; want to get lunch?"
"Uh…" Rainbow shook her head, still reeling. "No… I've got a… weather thing. Rain check?"
Twilight tilted her head. Her smile faded ever so slightly. "Oh. Okay, no problem. Catch you around!"
She trotted away without looking back. Rainbow's eyes followed her all the way down the street.
"This is such a bad idea."
Rainbow hunkered in the bushes across from the Golden Oak Library as the sun dipped below the horizon. Some ponies were already in bed, but she knew Twilight's better nature would keep her at the town council for hours until each mundane issue was resolved.
Knew. The thought panged her. Did she know Twilight? Did any of them? The more she thought about it, Rainbow realized she couldn't even remember the last time Twilight was sick. Maybe invulnerability was a perk of becoming an alicorn. But if so, why hadn't she said anything? Why would she keep a secret like this?
Rainbow sighed. She didn't even know why she was out here. Sneaking into Twilight's home certainly wasn't the most productive use of her time. Certainly more effort and more risk than just asking.
But she couldn't shake the feeling Twilight was hiding something, and her gut told her that there might be clues inside the library, where Twilight felt safe enough to let her guard down.
"This is such a bad idea."
Checking the street one last time, she darted through the shadows. Her hollow bones and magical wings made stealth almost second nature, hooves barely bending blades of grass, gliding like a whisper over loose gravel. A few quick flits around the library found an open upper window. Silent as a field mouse, she slipped inside.
After confirming Spike wasn't home, she started simply looking for anything that might indicate Twilight might be mortal. Tissues in the garbage from a bloody nose. A drop of blood from a kitchen knife mishap. A first aid kit with missing bandages. Any first aid kit at all.
She wasn't surprised her search came up empty. Twilight was an absent-minded egghead, but nopony Rainbow knew just went around casually bleeding on things. Plus, she had Spike to clean up after her.
Rainbow's next search was for any earmarked books with hints about alicorn immortality. She gave up quickly, realizing that the library was too large for a middling reader like herself to make any progress finding such a specific piece of information. Plus, Twilight would never earmark books; she just remembered the page numbers.
Briefly she considered looking for journals or private letters, but her conscience panged at the thought of invading her friend's privacy even worse than she had already. Nothing was worth that unforgivable breach of trust.
With all other options exhausted, Rainbow decided to do a once-over of Twilight's basement laboratory. She hadn't been down there often, but it was the last place that might hold answers.
The basement lab didn't hold any answers.
As far as Rainbow could tell, it was just a confusing jumble of wires, beakers full of unidentified liquids, crystals of various shapes, and hundreds of pages of near-gibberish calculations and notes. None of it seemed to answer her questions, at least not in any way that Rainbow could understand.
She was about to give up when she noticed it: A tiny door off one side of the lab, hidden in shadow and painted with a scary-looking symbol.
"Bio… hazard?" she muttered. "Huh." She stared at the door for a moment, chewing the inside of her cheek. "Well, if there's anything to find, it's gonna be in here."
She pushed the door. It wasn't locked, and swung open easily into a dark room.
It took a moment for the smell to hit her.
Rainbow reeled, gagging. She covered her nose but the air was so thick she could almost taste overflowing latrine and rotting meat. She staggered back to some semblance of fresh air. Her chest heaved, and her stomach churned.
Gathering herself, she pressed wingfeathers tight over her mouth and nose. It didn't do much good.
She edged closer to the room again, peering into the darkness. There was a shape there, a faint splash of color against the black. She fumbled blindly behind the wall, and her hoof found a switch.
A light gem in the ceiling illuminated, and she gasped despite the stench.
The shape in the middle of the room was Twilight Sparkle. Stretched out on an inclined table, limbs spread and bound. A clear mask covered her muzzle, fogging with intermittent breaths. Tubes ran from hanging bags of liquids into her elbows. An angled channel under the table, stained with dried refuse and blood, flowed to a drainage well at the back of the room.
Rainbow stared in shock for a moment before she found her senses.
"Twilight?" she said tentatively.
She stepped forward, and looked down at the mess under the table. Fresh blood dripped into a shimmering red puddle and ran down the channel toward the back of the room.
Her eyes trailed up to the source of the droplet: Twilight's hoof. Blood oozed from a deep, infected gash in the soft underflesh.
"I'm so sorry you had to find out like this."
Rainbow screamed and whirled in place, landing in a defensive posture.
Twilight Sparkle stood in the doorway.
Rainbow's stomach dropped. She looked at the Twilight on the table, then at the Twilight in the doorway, then back again. Her breath came in ragged gasps. "Wh-what in Tartarus?"
Twilight stepped into the room. "Look, there's no easy way to explain—"
Rainbow jumped backwards, bumping into one of the side walls. A shelf of tools rattled, and a rusty length of pipe clattered to the floor. She snatched it up between her forelegs. "Don't come any closer!"
"I'm not going to hurt you Rainbow, you're my friend. Just trust me—"
"Trust you?!" Rainbow shouted. "How am I supposed to trust you!?" She glanced at the unconscious Twilight again, then back at other Twilight. "What are you? A changeling?"
"No Rainbow, it's me," Twilight said, stepping closer again. Her face was earnest, pleading. "I'm me, I'm not a changeling, it's just—" she looked at the other Twilight on the table "—this is also me."
Rainbow shook her head, backing around the table. Her hoof slipped on something wet. She glanced around for an escape route. "I don't understand!"
"It's me," Twilight repeated. "Both of us. I learned, or I discovered, I'm not sure… I found a way to keep myself safe, and young. Like Celestia and Luna!" She took another step around the table.
Rainbow's hoof slipped again, and she had the sickening feeling of falling. She caught herself with a wing on the wall behind her, and looked down to see she was standing halfway over the drainage well at the back of the room.
At the bottom far below, was a tangle of bones, rotted flesh, and lavender fur.
When she looked back up, Twilight was directly in front of her.
"I was going to tell you Rainbow. Show you. I've found a way we can all stay together. We can be friends forever, if you'll just listen…"
Rainbow swung the length of pipe as hard as she could. It connected squarely with the side of Twilight's skull and sent her staggering across the room.
The Twilight on the table cried out as the side of her head caved in like an eggshell. Blood sprayed across the wall, and the clear mask went flying.
She gasped, chest heaving. Her eyes fluttered open. She looked at the other version of her on the floor, then turned. The side of her skull squished and crunched on the stone table, leaking red and pink. One eye jittered blindly at an off-angle, but the other looked at Rainbow with clarity. Her jaw creaked in what looked like three separate pieces but only voiceless gurgles sounded.
The Twilight on the floor stirred and dragged herself to her hooves, head completely intact.
Rainbow Dash glance between the two Twilight Sparkles. Her whole body was trembling. She looked at the bloody pipe in her hooves, then at the open door across the room.
She gulped, dropped the pipe, and launched herself toward freedom with a mighty beat of her wings—
—just as the door closed with a flash of purple magic, and everything went black.
Rainbow Dash blinked her eyes open to blinding light. Her head throbbed.
"Like I was saying," a voice intoned patiently, "Once the surrogate is in place, they'll absorb all the injuries you sustain."
She tried to move, but her limbs seemed made of lead.
"I'm almost sure this is how the other Princesses do it, even though they haven't told me."
She lifted her head and squinted toward the voice. Slowly a purple shape resolved across the room. It moved toward her, and the face came into focus.
Twilight Sparkle looked down at her. "It's really quite elegant, so long as you keep them alive."
"And you're sure she won't feel any pain?" a familiar voice asked.
Rainbow Dash felt a churn in her stomach, as another shape came into focus.
Rainbow Dash looked down at her.
"Of course not," Twilight said, lifting a clear mask. "Once she's under, she won't feel a thing."
Rainbow screamed, muffled, as the mask settled over her face.