The Night Will Last For As Long As Is Convenient
Ponies about the room yelped in surprise. On the pedestal before them, darkness and haze began to writhe and solidify into fat tendrils of magic. It pulsated, bubbling with a powerful energy that washed across all the onlookers in a thaumatic pulse. Then, with a flourish, the aura parted like a pair of curtains. It revealed a jet black alicorn in silver regalia, the starry magical aura reshaping itself to make up her mane and tail, which undulated in the frosty room.
"Oh, my beloved subjects," the alicorn drawled, her voice oozing with a smug malice. "It's been so long since I've seen your precious little sun-loving faces."
A pegasus with a rainbow hued-mane attempted a flying tackle against the alicorn from across the room, but was held back by a stetson-clad earth pony anchoring her down. Unceremoniously, rainbow tail grasped firmly in earth pony teeth.
"What did you do with our Princess?!" demanded Rainbow Dash, ignoring Applejack's muffled 'Woah there, Nelly'.
The outburst was met with a venomous laugh from the alicorn. "Why, am I not royal enough for you? Don't you know who I am?"
"Ooh, ooh, more guessing games!" gasped a pink-maned force of nature in the front row. "Um, Hokey Smokes! How about... Queen Meanie! No! Black Snooty, Black Snoot-" she managed to pipe in before an apple was unceremoniously stuffed into her mouth by Applejack. The cowmare seemed to excel in her ability to multitask.
"Does my crown no longer count now that I have been imprisoned for a thousand years?" the alicorn continued, ignoring the interruption as she leaned in close to interrogate the ponies around her. "Did you not recall the legend? Did you not see the signs?"
To her surprise, a voice answered her question from across the room.
"I did. And I know who you are. You're the Mare in the Moon... Nightmare Moon!"
The gasp that rolled through the crowd in response to this revelation was most satisfying indeed. Nightmare Moon smiled.
"Well well well," she muttered. "Somepony who remembers me. Then you also know why I'm here!"
The young purple unicorn who'd spoken out seemed to shrink under the withering gaze. "You're here to... to..." She gulped.
With a chuckle, Nightmare Moon found herself to be enjoying the moment immensely. "Remember this day, little ponies, for it was your last. From this moment forth, the night will last forever!"
Her chuckles exploded into maniacal cackling as her mane of dark magic swirled into a vortex above the room. Lighting shot out from her horn, sending violent flashes of light across the crowd. Oh, she was back to full strength. Her sister was gone. Everything was going perfectly!
"Wait, forever?"
The swirling vortex slowed as Nightmare Moon peered back down. Looking up at her, with one eyebrow raised in infuriating condescension, the purple unicorn seemed... unimpressed?
"Yes, forever," Nightmare Moon repeated. "Was I not clear in this?"
"Well, yes," the unicorn conceded. "It's just, in a socioeconomic sense, eternal night seems like a bad step."
"Socioeconomic... what in Equestria are you talking about, you foal?!"
"Okay, for starters. Food. While some plant life is capable of growing in low light conditions, the vast majority of Equestria is built on a farming bedrock. Crops that rely on sunlight for proper growth. While they can still grow in the dark, growth speed and yield is going to take a drastic hit. If you're in charge now, how are you going to make sure everypony has access to enough food?"
Nightmare Moon, prepared as she was for a grand monologue, found herself totally lost for words. "I... err..."
"Additionally," continued the unicorn. "Without enough sunlight, the entire ecosystem of Equestria would be thrown off balance. Plants wouldn't be able to photosynthesize properly, which means they wouldn't produce enough oxygen for everypony to breathe. And not just that, but animals that rely on plants for food would suffer too. It's a delicate chain reaction that could lead to widespread famine and chaos."
"Are you suggesting that the well-being of mere ponies and animals is more important than the eternal night I've brought upon them?"
"It's not just about the sentient life," the unicorn countered. "It's about the entire balance of nature. Without sunlight, the weather patterns would change drastically, leading to extreme temperatures and unpredictable storms. The very fabric of Equestria's ecosystem would be in jeopardy."
Nightmare Moon scoffed, her eyes narrowing at the irksome usurper of her grand moment of victory. "You seem to forget that I am the one in control now. I will dictate the weather and the land as I see fit, as they are now my playthings. My tapestry to weave in the patterns I deem most suitable."
"But at what cost?" pressed the unicorn. "You can't force nature to obey your will without dire consequences. The chaos that would result from your actions would bring suffering to all creatures in Equestria, including yourself."
All the other ponies murmured in agreement as Nightmare Moon's gaze swept over the crowd, her expression hardening. "Enough of this nonsense! I will not be swayed by your feeble arguments. My reign begins now, and none shall defy me! Even if you all have to perish by my hooves!"
The unicorn, infuriatingly, let out a small chuckle. "Well, it wouldn't be much of a kingdom for you to run if there's no living things in it, now would it? No pony or creature to bend to your whim. In fact, it sounds pretty boring to me."
As if to twist the knife in the alicorn's side, the assembled ponies in the room actually laughed along with this.
"Oh, forget it!" Nightmare Moon declared. "It's not worth the hassle!"
And with a puff of swirling stars and dark magic, she collapsed herself into a singularity. It pulsated, danced, and moments later spat out a young alicorn with a dark blue pelt and short-cut mane of starry blue.
"Whuh... what happened?" mumbled the juvenile Princess Luna.
