After a bit of fussing, Spike's return with assorted screws and different lengths of wire, some scroll sending, and a return by dragon mail of some crystal fragments wrapped in a scroll, Twilight A was ready with her device. The Twilights, Sunset, Sunburst, and Starlight were gathered back in the portal room. Spike had started yawning and been dismissed by Twilight. It was not clear whether he was tired or bored, but it was getting croweded in the laboratory anyway.
"The mirror is working just fine, see?" she said, demonstrating how the signal changed when pointing the device towards or away from the mirror.
"And me?" Twilight 1 asked anxiously.
Twilight A waved the device around in the vicinity of Twlight 1. "Nothing," she said.
"Woohoo!" Twilight 1 said, jumping into the air and flapping her wings, "I didn't kill myself!"
Sunset raised an eyebrow at that.
"Errr... sorry, it's just a relief," she said.
"Now wait a moment," Sunburst said, holding up a hoof, "What if the mirror is overwhelming your own signal? We should go somewhere far away from any dimensional nonsense just to be sure."
Twilight 1 dropped to the ground, crestfallen, her wings sagging.
"Oh we should stay away from the Everfree portal too," Sunset said, "So maybe on the opposite side of town?"
"Right, in that case..." Twilight 1 said, lighting up her horn. With a soft 'pop' they were outside of town on the road towards Canterlot.
"Woah," Twilight A said, a little disoriented, "That takes some getting used to..."
"It doesn't take too long," Twilight 1 said, "What does it say? What does it say?"
Twilight A waved the device around.
"Ok, so I'm getting nothing here... let me adjust the sensitivity..." she said, turning a knob she had added to the side. "Alright, so there's your castle... Were the other mirrors in that city built into the mountain?"
"That's Canterlot," Starlight supplied, "I'm pretty sure Celestia has them hidden in the catacombs somewhere."
Twilight A nodded. "Ok and... nothing from uhh... Twilight," she said, "Twilight 1 I mean."
"Once again, woohoo!" Twilight 1 said, forgoing the leap this time.
"And again, would it show up now or only right after?" Sunburst said.
"Hmmm, yes I suppose we would need to test it right when she died and respawned..." Twilight A said.
"But what if that kills another her?" Sunset asked.
"When you think about it, that was never very likely," Starlight said, "Her mind would have to push out another alicorn's. This whole test was on the basis of 'better safe than sorry'. Same principle as time travel."
Twilight 1 glanced upward. There was clear sky above them.
"Ok, so very low probability of hurting anyone," she said, "And I can't be sure when I might be forced to respawn. I think we have to try it."
"Ok, but how are you..." Starlight began. Twilight's teleport cut her off.
"Where did she...." Sunset also started a sentence before hearing a faint sound and stopping.
"Uh, maybe we should step back," Sunburst said, looking up, "Just in case.
Everypony glanced up, then took several steps backwards in a circle. Twilight A kept her device trained on the plummeting alicorn as the faint sound became more distinct.
"Hooooooooooooooo!" came the sound as she neared the ground, head-first. There was a rather disturbing 'crack' and 'squelch' sound as the rather unforgiving ground met flesh not designed to take that much force. Starlight quickly threw up a shield around herself and Sunburst. The other unicorns, despite their distance, found themselves covered in rather more bodily fluids than they wanted. Which is to say, more than zero.1
"Huh," Starlight said, lowering the shield, "That sounded... eager."
"Injuries do trigger a release of endorphins and adrenalyn," Twilight A said as she stared at her sensor, trying very hard to ignore what was uncomfortably close to her own fresh corpse on the ground in front of her, "Ordinarily that's to counter the pain. Maybe with the pain gone she's coming back with a runner high."
"A what?" Sunburst asked.
"Trotter's high," Sunset translated.
"Oooh," Starlight said, "That would explain a lot."
After a bit of awkward silence, another question occured to Starlight.
"Huh, I wonder what would happen if we revived this corpse?" Starlight asked, "I mean I don't think we could do it with a broken neck, but what if she died from an electric shock or something?"
"Maybe we should address that next," Twilight A said, "Might pose some ethical questions of its own."
Starlight lit up her horn and a glow surrounded Twilight 1's body.
"Well I'm not picking up any magic emission," she said, "And... hmm..." Her aura shifted to a lighter shade of purple and focused around Twilight 1's head. "No brain activity either, as far as I can detect, but then I'm no medical unicorn."
"Hold on everypony, she should be back just about..." Sunburst began, "Now." He pointed a hoof towards a spot behind the corpse. When nothing appeared, he pushed up his glasses to cover his embarassment. "That would have been a good time to get that right," he said.
Just then, Twilight 1 appeared with a 'pop' directly in front of Twilight A, leaning over her device and into her face.
"Gaaah!" Twilight A started back.
"Well? What's it say?!" Twilight asked eagerly.
"Uhh..." Twilight A said as her heart beat a mile a minute. She glanced down at her device, which was poking into Twilight 1's... chest, she guessed would still be the term? The detector still showed the baseline.
"Nothing," Twilight A said, "I think we can reasonably safely assume you aren't getting bodies from another dimension."
"Again, woohoo!" Twilight 1 said, more subdued this time. "Now that that's out of the way, I think we have time for one more test today."
"Hmmm, well the fastest would be to see if you can respawn across dimensions," Sunburst said, remembering the previous list.
"First I think we should bury this," Starlight said, gesturing with her hoof at the Twilight corpse just in front of them.
"Oh, right... we need to come up with a more efficient disposal method," Twilight 1 said.
"You could just dump them in a volcano," Starlight said, "There's one in the dragon lands that would work."
"I'm not really familiar enough with it to teleport there," Twilight 1 said, "I suppose I'll need to make a trip there first. We still need to deal with this one."
"Hold on I got this," Starlight said. In seconds she had popped out a perfectly shaped grave with magic, thrown Twilight's body in there with the same, then dropped the dirt back on top. The other ponies present boggled at her.
"Uhhh... should we be concerned?" Sunset asked.
Starlight blushed. "Buried alive was one of the... ideas I toyed with when I was looking for revenge against Twilight," she said, then hastily added, "Not that I would have actually done it! I realized pretty quickly it was going too far." She then added under her breath, "Besides, she could have just teleported out."
***************************************
Ignoring that, it was not too long before they were back in front of the mirror portal. Sunset and Twilight A were wearing the saddlebags again.
"You two need to be home soon anyway, right?" Starlight asked Sunset and Twilight A.
"Sort of, but it's actually the weekend over there," Sunset said, "So it's not as big a deal."
"Oh right, then you'll be able to help for the next two days!" Twilight 1 said excitedly.
Twilight A looked around a little nervously. Seeing this, Sunset spoke up.
"We do have homework to do, plus plans with the girls," Sunset said, "So I think..."
Twilight A held up a hand... er, hoof, and took a deep breath.
"No, I can do my homework in an hour, and we don't have plans with the girls until the evening," she said, "I was a little disturbed seeing that body, but I can endure. If I'm going to do medical research some day, I'll have to get used to that sort of thing."
"Oh, you want to be a Doctor?" Twilight 1 asked.
Twilight A shook her head. "Medical researcher, not quite the same thing," she said, "And that's only one of my options. I'm thinking of going to a liberal arts school so I can delay that choice for a little longer."
"Huh, your educational system sounds complicated, "Starlight said.
"It has its moment," Sunset said.
Twilight 1 clapped her forehooves together eagerly.
"Alright, you too! Let's get going!" she said, "I'm really curious to see how this works!"
"Is it alright if I leave my equipment here?" Twilight A said, "That'll give me room to bring some more instruments tomorrow."
Twilight 1 positively beamed. "Of course!"
"Well, see you on the other side," Sunset said, then to Sunburst and Starlight, "And I guess I'll see you two tomorrow?"
"Actually we have to deal with some parent-teacher conferences," Sunburst said.
"I'm guessing we'll have some concerns about students seeing our former headmare throwing herself off the top of the castle... repeatedly," Starlight said, "Not looking forward to that one..."
"Oh, once they see that I'm fine, it'll all work out," Twilight 1 said.
"Right, later then," Sunset said, gesturing Twilight A through the portal and then following her.
*************************************
On the other side, Twilight A stepped out of the portal, her backpack back to being just that. She only had to wait a moment for Sunset to join her.
"So... Want to bet on how big that pile will be by tomorrow?" Sunset asked. Twilight A blanched. Sunset winced in response.
"Ok, so it's a bit morbid," Sunset said, "But it's not like anyone's really getting hurt."
"I suppose..." Twilight A said, glancing down at her watch2, "It's still disturbing."
"Eh, think about it like a video game," Sunset said with a shrug, "One of those ones where the bodies don't instantly vanish."
"Right... so do you think this will work?" Twilight A asked.
"I guess we'll find out," Sunset said, looking around, "She said she would try to pop up right here by the statue."
Twilight A focused on her watch as the second hand went around.
"So that's a minute," she said, "Do you think the time we spend in transition counts?"
"Huh, good question," Sunset said, putting her hand to her chin. "It always seems to take time, but apparently the Sirens were outside of time before they came here, so maybe we are too when we're in-between?"
"Hmmm, might make a good research topic later," Twilight A said, "How long do we wait?"
"Fifteen minutes?" Sunset said, "Isn't that how long you're supposed to wait for the professor?"
Twilight A giggled. "That's mostly a myth," she said, "Although I've heard some colleges have adopted it."
At that moment, a flash came from the portal. Sunset and Twilight A focused on it rapidly. Out stepped another Twilight, this one without glasses.
"Still weird to see that," Twilight A said.
"Huh, that's odd," Twilight 1 said, "I meant to come in right behind you two..."
"What happened?" Sunset asked.
"Oh! Well I threw myself off the tower as usual," she began. Twilight A winced again. "Right, not that part," Twilight 1 said, "Anyway, I went to the misty place like usual, but when I thought of where I wanted to go, I didn't immediately go there. I tried to focus more on the place, picturing it as best as I could, when a mirror appeared in front of me. I stepped through it and, well, here I am."
"Huh," Sunset said, blinking, "That's interesting. I always through the portals changed our bodies, but do they make entirely new ones?"
The Twilights thought about this for a moment, but Twilight A shook her head first. "I don't think so. Remember the portal on that island? If it were making a new body, our old one would have to stay in that in-between place, meaning the portals would all have to be connected. And then why would each one always lead to the same place?"
"Plus when I first came here, I tried putting just part of my body through," Twilight 1 said, "And I had a hoof on the end of an arm for a moment."
"That sounds strange," Twilight A said.
"Moreso than being an upright nearly-hairless simian?" Twilight 1 said, gesturing with her hands with a grin.
"Or than being a tiny, talking, equine with magic?" Twilight A responded with a laugh, "I guess you're right."
"So then why could you only come through the portal?"
"I don't know," Twilight 1 said with a shake of her head, "I was going to try going the other direction, but if I can't respawn normally here, I'd rather not die here, just in case."
"Yeah, and we don't have the pull to keep people from asking about the body," Sunset said, pacing a bit with her hands gathered behind her back. She stopped and looked over her shoulder.
"Maybe it's the Equestrian magic?" she suggested, "It's strong here."
"Oh, so maybe she could pop up near where we found the stones?" Twilight A said.
"Geodes," Sunset said.
"Technically only 2 of them are geodes," Twilight A said, "A geode has to have a..."
"Separate type of rock inside the first," Twilight 1 joined in, so that they both said that at the same time. Twilight A looked a bit startled.
"Oh right, I guess you would know. have you also talked about rocks with Pinkie's sister?" Twilight A asked.
"Oh, yes!" Twilight 1 said, "Maude's research is a bit dry to some, but it really is quite fascinating! Is your Boulder also extrusive igneous?"*
"Yes! And have you heard how they met?" Twilight A said.
"Right right, we all know the dramatic and heartwarming story of how Maud met Boulder," Sunset set, cutting them off before they nerded out too much. Not that she'd have used that phrasing. "So tomorrow I guess we can take you out to Camp Everfree to try there." Sunset got a mischevous grin on her face. "And Twilight... errr, Twilight A... here can see Timber Spruce."
Twilight A blushed, and Twilight 1's ears perked up.
"Timber Spruce?" Twilight 1 asked.
"He's..." Twilight A began.
"They've been seeing each other," Sunset said.
"Huh, I don't think I know a Timber Spruce... is the Maud here seeing Mudbriar?"
"Huh? Maud is seeing someone?" Sunset asked.
"Pinkie hasn't said anything, so probably not," Twilight A said, shaking her head, "Of course, people here seem to be a little younger than ponies there. Are you seeing someone?"
"Somepony," Sunset corrected.
"No... my duties keep me pretty busy," Twilight 1 said. Sunset rolled her eyes.
"I mean I guess the dead bodies would put most boys...stallions... off. You know I tried to find Equestria's Timber Spruce when I was there," Sunset set.
"You did?" Twilight A asked, "What was he like?"
Sunset shrugged. "I don't think he exists. At least there weren't any records in Ponyville or Canterlot."
"Why were you looking for him in the first place?" Twilight 1 asked.
"You seemed like you could use the help," Sunset said flatly.
"Do not!" Twilight 1 said, bristling a bit at Sunset's line of thought.
"Well, it was a dead end anyway," Sunset said with a shrug, "Odd how similar our worlds are when they're also so different. Like here, Maud found Boulder on a family trip to an island in the sea, but I don't remember any such islands near Equestria.
Twilight 1 shook her head. "No, she was doing research in the Dragon Lands."
"Hmmm... Well nothing to be done about it today," Sunset said with a shrug, "Maybe you can try with another dimension, too. One with more magic. Might get some data on dimensional similarities there, too."
"Oooh, like the mirror dimension that used to have the evil Celestia and Luna!"3 Twilight 1 said. Sunset raised an eyebrow.
"Huh, that does sound interesting," she said, "but tomorrow. Sleep time now. And that means you too, Twilight.... Errr, Twilight 1."
***********************
That evening, as Celestia was going to bed and Luna was waking up, a scroll popped onto their dinner/breakfast table.
"Oh, that must be Twilight," Celestia said, "I wonder how she's coping with her newfound powers?"
Dear Princesses Celestia and Luna
The first day of the First Annual Alicorn Respawn Research Conference has been a qualified success. (Sorry for the name, Princess Celestia, but it's short and memorable!)
Luna giggled at Celestia's mild annoyance.
Today, after some initial concern, we determined that the new alicorn bodies are not extra-dimensional copies whose bodies we have usurped. This concern caused quite a detour, and we had to request help from Canterlot High.
"Hmmm, I suspect Principal Celestia does not have to deal with QUITE this sort of issue," Celestia said as she glanced back at Luna. Luna shrugged.
"Letters between my counterpart and I mostly discuss current events and how to deal with irritatingly composed elder sisters," Luna said. It was Celestia's turn to giggle at her sister.
We have also made the unusual discovery that I cannot simply 'spawn in' at Canterlot High, but rather enter through their portal when I try. With your kind permissions, we intend to see if this persists across other dimensions tomorrow. Do you two, with your lengthy experience, have any knowledge of this?
Luna sighed. "I suppose we shall have to find a dimension we have not been to in awhile," she said, "We do not want there to be another incident like that with Lord Sombra."
On seeing her sister's downturned expression, Luna added, "Apologies, sister. I did not mean to stir bad memories."
"It's fine," Celestia said, waving her hoof, "He is alive, and some day we shall find a way to restore him."
Yours, Twilight Sparkle
PS: I'm starting to worry respawning might be a bit addictive. Do you have any advice on this?
Luna giggled again. "Ah, it seems she takes after her teacher in yet another way!" Luna said.
"To her credit, she is approaching it methodically and with good intentions," Celestia said, a note of pride in her voice, "I was merely having fun."
"So what shall we do?" Luna asked.
"I'll have to make time to visit her conference," Celestia said with a touch of resignation, "I suppose I will have to make a statement about all the corpses, too. It has been a few hundred years."
Luna started. "Sister? What were you up to in my absence?"
Celestia shrugged. "There was a particuarly boring chancellor a few centuries back," she said, "The first time I leaned back and fell out of the window was mostly an accident while I was asleep but, well... I found it created enough of a scene to liven things up a bit. Of course HE figured it out after the second time, but he had a hard time explaining it to passersby... or visiting dignitaries... or the Council."
Luna chuckled. "An amusing prank, but perhaps a touch cruel."
Celestia sighed. "You weren't there. It was a very boring century all around."
**************************************
1 To their later dismay, Sunset and Twilight A discovered that blood-stained fur translated into blood stained clothing when they went back through the portal. Why Starswirl would have set it up that way was a mystery that Sunset resolved to address on her next visit to Equestria.
2 Twilight A would later wonder where the watch had gone when she went through the portal, or if it had been there and she just had not noticed it. Seeing a dead body of the person... or rather pony... standing next to you had a way of making one forget about functional accessories.
3 As this happened in the comics, it exists in a state of having both happened and not happened simultaneously. Appropriate, really, given the subject matter.
*From Rock Solid Friendship, Boulder is magnesium-rich basalt that's about 200 years old. Basalt is an extrusive igneous rock, meaning it's formed by the cooling of magma that reaches the surface. Magnesium-rich basalt cools solidifies more rapidly than the iron-rich version due to the lower higher melting temperature (which means it solidifies more easily). It is most commonly found around volcanoes. Maud's statement that a stripe on Boulder gives his age could only be known if she found him in situ (meaning in the place where he formed, without intervention from humans or ponies). The rate of volcanic activity can be predictable over thousand-ish year time scales, so seeing the layers of flows around him could give an estimate of age. Alternately, basalts are sometimes magnetic, and field can be 'frozen in' to them, giving the iron compounds in them an orientation. If Equestria's magnetic field changes at regular intervals, that could also give an estimate of age. Either way, the age estimate would require information we aren't privy to.
Please note: I am not a geologist by trade, so the above is based on what I could gather from research for both this and a review I did on Rock Solid Friendship (https://www.youtube.com/watch?v=d8CjxFpLODg) Any geologists in the audience, feel free to let me know what I've got wrong.
And yes this footnote primarily exists to give this chapter an educational component.
Thanks to Magnum Hocus for pointing out the rather elementary mistake I made in the last note. Corrections are indicated by a strike-through of the old phrasing.