On a great empty plain before the gate to Tartarus sat two alicorn sisters taking tea, and with them a trembling unicorn failing to take tea and instead spilling it spectacularly from nervous hooves.
“A fine morning you have conjured for us, Celestia!” The bluer of the two sipped daintily from fine silver-edged china. “Honey?”
“No thank you, Luna. Yes, I thought you’d enjoy the bit of purplish tinge I added to the sunrise. I rather like that shade of lavender,” smirked the alabaster sister, “as do you, I hear! Sugar?”
“Yes, please. More tea, dear Twilight?”
The reply was almost drowned out by the quavering clatter of cup against saucer. “P… P… Princess! L… Look! Cerberus is…”
The elder alicorn glanced across the plain toward a distant hill where six tree-tall ears could be seen shaking, their owner presumably the source of what could only be described as a distant, titanic whimper. “Isn’t he cute when he’s like this? Just makes me want to hold him and squeeze him and love him and call him George.”
”Indeed, sister, the legendary hound is adorable in his fright. Scone?”
Twilight’s mane earned several new entries in the her thesarus under ‘frazzled’. “But Cerberus isn’t guarding the Tartaran Gate, and that means… There! Something’s emerging! We have to summon the Royal Guard! Gather the Elements! Go postal! We -“
An indigo hoof to the muzzle silenced the smaller mare. “No need for such hysterics, young Twilight Sparkle. Trust your Princesses. We have planned for this moment for ten thousand years. Admittedly we were off by six months or so, but in the grand scheme, who really notices?
From the gaping maw of the Tartaran rift emerged a flowing, lumpen mass of tentacles and hate. Its viscous black body flowed like a mountain of sentient tar whose skin bubbled with festering boils, each of which resembled nothing so much as a screaming face. Its vast bulk stood taller than Canterlot Castle and it cast a lengthening shadow across the plain and over a certain elaborately worked tea-table.
“That, my most treasured pupil,” said Celestia, pointing offhoof at the boiling mass of insanity crawling its way out of the festering gorge,” is known by many names. Some call it Yog-Sothoof, others refer to it as the Damwich Horror. More properly it is Atum, child of the Soil, who was born in the first age when the elder gods were corrupted. Its mother was the Earth, figuratively speaking, and its task is to eat wayward gods. Crumpet, Luna?”
Luna buttered a light pastry before continuing. “Not another just yet, but my thanks nonetheless. Indeed, Twilight, Celestia speaks true. In more ancient mythologies this beast is named Demogorge, the God-Eater. It emerges every few millennia when it senses that a divine power has overstepped its bounds and must be consumed for the good of the universe. After it dines on immortal flesh, it retreats to its ageless slumber.”
“So it’s going to eat one of you? Oh, Princesses, please! Don’t sacrifice yourselves! There must be another way!”
The sisters looked at Twilight with amused grins and a hint of bagel breath. “Don’t be silly, Twilight! That’s what we brought him for.”
Only now did the twitching unicorn notice a statue across the plain, which appeared to have been set perilously close to the fallen Gate of Tartarus. It stood two ponies high and yet was dwarfed by the smallest of the slime-coated otherworldly appendages oozing past it. From a distance it was hard to discern its features but it appeared to be cracking and splitting even as it was subsumed by the crawling chaos around it.
The statue crumbled to dust amid a blaze of light, its formerly resident Draconequus cracking his back dramatically. “Free at last! Free at last! Thank me almighty, I’m free at last! Now girls, was that any way to treat the life of the party? I don’t see your precious Elements this time, so if you’ll excuse me, I have a big old storm of Chaos to… Hello, recently liberated chaos god here! What is everyone looking at? Something behind me? Really, ladies, that’s the oldest joke in the …”
CRUNCH munch munch munch BUUUURRRRP went the Demogorge before it shrank down its infernal hole.
Celestia stared across the distance, concentrating deeply. “Should we tell Atum he’s got an antler stuck in his teeth?”
Luna reclined and looked thoughtful. “I wonder if he tasted like chicken?”
A relaxing tea in front of the gates of Tartarus while a god-eating creature of legend emerges? Perfectly possible with Discord around! While the somewhat callous attitudes of Celestia and Luna towards their foe was a bit disconcerting, it was still quite humorous in a dark sort of fashion. Dragging Twilight along as the everypony was a good idea as well.