Now, don’t suppose for a minute that I’ve NEVER liked Rainbow Dash, heavens no. We used to be very good friends, respectful of each other’s skills, and bound together by the trials we had faced. I even bore the many injuries she occasionally would send me, intentional or not, with tolerable pride. But when she deliberately insulted me by striking my beloved library with uncalled for lightning, that was the last straw. I vowed revenge; not immediate, but drawn out, well planned vengeance. So I waited, biding my time, planning it out, step by step, all the while never once giving her any reason to doubt my friendship.

Now, she had one weak point, Rainbow Dash, and that was apple cider. She was wild for the stuff, could never get enough. In all other aspects she was headstrong, determined, and, of course, loyal. But all it took was the very mentioning of apple cider to turn this solid pillar of will into a bibulous, soppy mess.

That, I determined, was to be her undoing. I myself was considered a bit of an aficionado in cider rings, and bought largely whenever I could.

It was in the midst of the wild regalia of the Nightmare Night festival when I met Rainbow Dash and set my plan into action. She had already become somewhat inebriated on the sweet golden nectar previously mentioned, and had even woven some jolly bells into her multichromatic mane.

“Hey Twilight!” she said from her usual perch of thundercloud, “How’s Nightmare Night for ya?”

“Oh just fine, Rainbow”, I replied, grinning eagerly at the sight of my friend. “Candy, punch and games galore! Though you see to be having a ‘ringing’ good time yourself!” I giggled and gestured towards her bells.

“Yeah, yeah” she groaned, trying to muffle them with bits of cloud, “I lost a game of Cata-Pumpkin to Rarity, and I have to wear these all night. I swear she used her magic though, and you wouldn’t believe how hard it is to sneak up on people with these things on!”

“Ah well, you can’t win em’ all, right?” I teased.

“Yeah, yeah whatever. So where’re you off to now, Miss Bookworm?”

“I was actually just off to see Rarity myself about a keg of apple cider I recently purchased. You see, I-“

“Whoa, whoa, whoa, stop” Rainbow interrupted. “You don’t mean a keg of genuine Sweet Apple Acre cider, do you?”

“Yes, I-”

“THIS late in the season?”

“Yes, but-”

“On NIGHTMARE NIGHT?!”

“YES Rainbow, I recently purchased a keg of what I believe to be grade-A, top notch, five star, blow-your-horseshoes-off, one-of-a-kind, Apple Family Cider on Nightmare Night” I was beginning to get exasperated.

“No WAY!” Rainbow Dash was beginning to get excited. “How did I not hear about such a great deal? Wait... then why do you need Rarity?”

“I was getting to that. You see, I, like you, have my doubts concerning its authenticity. I wanted to check with you to be sure, you being such a connoisseur, but you were not to be found, and I didn’t want to lose the bargain.”

“Imagine,” she said, as if in a dream, “A whole keg, this late…”

“Yes, but seeing as you’re busy with your usual pranks, I’m off to find Rarity to aide me in my assurance. With her discerning tastes, she’ll no doubt be able to-”

“Feh, Rarity? That glitter-head wouldn’t know apple cider from lemonade.”

“Really? I was talking just last week to Applejack, and she thinks Rarity’s taste may even out-do your own.”

“Horse feathers, let’s go!”

“Go where?”

“To check out that keg, egg-head!”

“No Rainbow, I know how much you love your pranks, and as you say, this is the best night for them. I won’t impose upon you, and beside, Rarity will surely-”

“-fail in her evaluation. Come on, I can pull pranks any day of the year, let’s go!”

“Rainbow, no. I must confess, it isn’t the distraction from your pranks that bothers me, it’s where I keep the cider. Remember when Rarity was kidnapped by the Diamond Dogs?”

“Oh course! Man, we kicked those mutts’ tails off!”

“Exactly. Well, after that defeat, they left in shame, leaving their extensive caverns open for anyone who wanted use them. I spent months at it, but I finally converted them into my own personal cider cellar. I even hired some colts to dig a tunnel connecting it to the library.”

“Wow, sounds cool! What’s the problem?”

“Well, it’s very cramped and musty in the catacombs, and I know how pegasi can get claustrophobic in tight, dark spaces.”

“HAH! Is that all? I was fine the last time we went down there, wasn’t I?”

“Yes, but that was an emergency. I’d hate to risk making you uncomfortable…”

“That’s it, first you wave cider in front of my nose, and now you insult my bravery. We are going to your cellar, and that’s that!”

And with that, she picked me up on her cloud and sped us off in the direction of the library.

I had instructed Spike to stay in the library and hand out sweets to the young foals, and that I would be gone all night. I knew this was enough to ensure his own departure as soon as my back was turned. He most likely stuffing his own face with candy and trying to impress Rarity at spider-toss. Hopefully not at the same time.

Upon entering the library, I levitated the table with the pony-bust into a corner, revealing a trapdoor in the floor, which I opened to reveal a flight of stairs, spiraling down into the interminable darkness.

"Wow, Twilight,” said Rainbow as we descended. “Your library just got 20% cooler!”

I sighed inwardly. Would she ever stop using that blasted joke? Then I remembered; yes, yes she would.

We got to the bottom of the staircase, and I lit my horn, casting a cool, lavender light through a small tunnel entrance in the wall.

“Well Twilight, shall we proceed?” Rainbow asked raucously. So intoxicated was she that it was required for her to drape a wing over my shoulder and steady her gait, but we managed well enough, and began walking.

“Where’s this mystery keg?” she asked, peering into the blackness.

“Oh, it’s a ways farther on. We haven’t even gotten to the main chambers yet. But until we get there, observe the perfectness of this tunnel”

“The tunnel?”

“Yes; see the exact smoothness of the walls, and precise symmetry of its shape. And then imagine, the fact that this unpropped tunnel supports no less than 20 yards of solid earth above our heads, and that... Rainbow, are you all right?”

For, during my small speech, Rainbow had grown quite pale and shaky, a light sheen of sweat forming on her face.

“…huh? Oh, y-yeah, I’m f-fine.” Her wings began to flutter nervously, her avian instincts looking for a way out of this oppressive atmosphere.

“I knew it,” I spoke in a self-chiding manner. “This tunnel is far too cramped for your pegasi sensibilities. Come on, Rainbow, we simply must go back! My being gone isn’t important, who cares for straight-and-narrow Twilight Sparkle on Nightmare Night? But you are an integral part of Ponyville Nightmare Night tradition. Where would everyone be without your pranks? Come, we must return to the surface, and besides, I can always ask Rarity to-”

“I said, I’m fine!” Rainbow Dash shook her head and steadied herself, trying to look brave. “A little claustrophobia won’t kill me. Let’s just keep going.”

“So be it, my friend, I meant not to offend you. But still, here is a barrel of carbonated cherry-cider. What say you to a drink? It’ll do us both good.

Rainbow meekly nodded her head, and I quickly filled up two nearby mugs with the bubbly red liquid.

Rainbow eagerly lifted the drought to her lips, but thought of something else at the last second, and suddenly proclaimed, “To those cowardly Diamond Dogs! Wherever they are now, I hope they’ll still getting their flanks kicked, one hoof-print at a time!” and she drained the mug in one breath.

“Here, here,” I added merrily. “And to Rainbow Dash, the most ferocious flank-kicker in all of Equestria!” and I likewise drained mine.

Having braved ourselves against the elements, we continued on to the main chambers.

As Rainbow’s nerve grew stronger under the influence of the cider, so did her need to show it.

“You know Twilight,” she said, some minutes later, “These caves are actually pretty cool”

“Say what you want about the Diamond Dogs,” I replied, the cider emboldening my own nature, “they were certainly clever architects. And fearsome fighters, according to popular legend.”

“Hah! Fighters? Don’t make me laugh, Twilight, we had those dogs howling for mercy.”

“And yet their motto would have you think otherwise; Nemo nocet me sine contra retributionem!”

“What in the hay does that mean?”

“Oh, silly Rainbow, it’s dog-latin, meaning; No one harms me without facing retiribution!”

“Hey, not bad! I think I’ve heard something like it before...”

“Oh, no doubt, you’re very familiar with the idea.”

We were now passing through a particularly tight section of tunnel. We could no longer walk side by side, and our heads occasionally scraped the roof, bringing small showers of dirt and debris raining down over our manes. I took the lead to properly cast the light, but I could tell by the sound of Rainbow’s heavy breathing that the tight space was beginning to affect her again.

“Oh, Rainbow Dash, this is simply terrible, and it’s all my fault! These passages are simply much to narrow for you! Come let us go back and-”

“I’m going on, and that’s final! But still, how about another cup of the good stuff?”

I willingly indulged her taste with a particularly strong ’98 vintage, and she was soon brazened. Her eyes blazed with a fiery light, both eager and somewhat grotesque, and the bells in her mane tingled merrily at her increasingly unsteady gait. Her entire weight now leaned against me as we continued.

We walked on for quite some time in a half-stupefied silence, descending another flight of stairs and passing through more dank archways until at last we came to farthest recesses of my catacombs. The air was thick and dusty, but what a spectacle greeted us!

I had taken particular pride and care in this room, for it was here that I had put to use all the spare gemstones the Diamond Dogs had left lying around, decorating the walls in a most tasteful fashion. The sparkling jewels reflected and increased my magic light tenfold, requiring me to reduce it a little. Rubies, emeralds, sapphire, topaz, diamonds; all glittered and shimmered in decadent swirls of blinding color, very nearly putting my companion’s cutie mark to shame.

“Wow...” said rainbow, struck dumb in awe. “What Rarity wouldn’t give to find this place!”

“Not to worry, my friend,” I replied, guiding her towards the furthest wall, “Only two ponies in Equestria know about these chambers, and they’re both here in this room. Come, the keg is just through here.”

I had led her to the far wall of the chamber, which was the only wall not decorated by gemstones. The jewels had in fact been thrown down from their usual place, and formed a sizable pile near the entrance. The wall itself had a hole, a kind of small tunnel, dug into it, just big enough for a pony to fit in side.

“Therein lies the Cider, my friend, just in the back.”

Rainbow Dash walked into the gloomy niche, and was immediately halted by a wall of solid rock. Standing dumb and drunk and she was, it was easy for me to levitate the chains I had placed specifically there, wrap them around her legs and wings, and securely fetter her to the wall.

Locking the chains with a fine padlock, I withdrew from the tunnel and again attempted to speak to my friend; “Oh, see what I’ve done, Rainbow, I’ve gone and put you in the tightest space yet, you simply must return with me to the surface. No? You’d rather stay? Well, if that’s the case, then I have no choice but to leave you.”

“B-but,” she replied, her intoxication wearing off somewhat at this new shock, “The-the apple c-cider!”

“Indeed,” I replied, “the apple cider.”

Having said this, I turned towards the pile of radiant gemstones, and, levitating them away, I reveled a large quantity of brick and mortar. I quickly set to work with them, and began to wall up the small tunnel.

I just finished putting down the first layer when a low moan escaped from the darkness of the niche. Apparently, Rainbow Dash’s drunkenness had worn off completely; it was not the moan of a drunk, but rather, one of abject despair. I put down another three layers of brick, when I was suddenly shocked by the loud rattling and agitation of the chains. I sat down among the gemstones a listened with a keen ear, taking pride in my fine fettering of the pugilistic pony. Presently the noise ceased, replaced by a dejected silence, and I resumed my labors. I laid down the filth layer, the sixth layer, the seventh and eighth. The bricks were now up to my neck, and, again laying down my labors, I cast a few rays of light into the niche, dimly illuminating the haggard form within.

Much to my surprise, I was thrown back by a sudden shriek of terror, issuing from the throat of my friend. The screams and wails stretched on, echoing and doubling in strength off the jewel-studded walls. I was delighted. I leaned against the mason-work and joined Rainbow in her screams. I aided, I supported, I outdid her screams in volume and power. All this and more I did, and the madness grew.

It was now midnight, and my labors were approaching an end. I completed the ninth, tenth, the eleventh and final layer of brick. There now remained only a sizable hole in the top of the tunnel, which I was about to block up with a nearby stone, when suddenly, from the dim interior of the niche, there came the weak voice of my dear friend;

“Heh heh heh ha ha, oh Twilight, he, th-this sure is a good prank! Oh ho, you sure got me! Ha ha ha, we’re sure going to have a good laugh at this over the cider!”

“Yes,” I replied, “the excellent cider!”

“Ha ha ha, yes, yes, that good Sweet Apple Acre Cider! Hee hee hee! But still, it’s getting pretty late! Like you said, how will Ponyville get on without my Nightmare Night pranks? Heh heh, an excellent joke, Twilight, but come on, we should really be getting back, right? Our other friends might begin to worry, let’s go.”

“Yes, let’s go.”

There was a pause, then suddenly;

“In the name of Celestia, Twilight, let me out!”

“Yes,” I responded coolly, “in the name of our dear, sweet, Celestia.”

At these words I listened for a reply. Much to my disappointment when there was none. I called her name;

“Rainbow Dash!”

Still no response. I climbed against the bricks and cast a few more rays of light into the niche, and called again;

“Rainbow Dash!”

I received no reply but a slight tinkling of bells.

I suddenly shuddered and felt sick (no doubt the result of too much time in the dank, oppressive atmosphere). I levitated the finishing stone and plastered it into place. I then resurrected the display of jewels and quickly left.

And in the 20 years since, nopony has ever re-entered that chamber.