A wicked smile crept onto Sombra's lips as he confidently marched down the empty hallway. His shadow was growing over the Crystal Empire, just as it had once done before. The soldiers of this great city now obeyed him, following his every command and leaving the Empire defenceless before him. Now, he was within the palace. Within his palace, and before long he would claim it as his own yet again. But first, he had to deal with the family who already ruled here. The Princess and her husband of course, but also their bouncing baby girl. He chuckled grimly at the thought of just how distressed the two parents would become once they realised who he was going for first, and speaking of whom, he now approached the chosen door, pushing it open and entering the chamber within. Sure enough, there she was. Flurry Heart, sleeping soundly in her crib, completely unaware of the dark figure who now loomed over her, even as the ancient King began to speak.
"Well now, what a sweet little child. Certainly would be a shame if, well..."
His grin widened.
"...if something terrible were to happen to her."
With no further words, his horn glowed its sickly dark magic glow, and within only a moment, Flurry was unceremoniously yanked from her slumber, floating above her bed and, at last, awakened. She squeaked with great distress over what was happening, trying to orient herself as Sombra's spell held her upside-down. And it was here when the young filly finally saw her captor, still smiling evilly as he stared right into her eyes. Flurry had never seen this stallion before, but she already knew he was somepony bad, as evidenced by the way she shrank before him. Sombra laughed out loud.
"Yes, you are wise to fear me, child. But rest assured, no harm will come to you."
He cast a glance to the side.
"Your parents, on the other hoof..."
At the mention of her Mother and Father, something changed in Flurry. Her fearful expression melted away, replaced instead with a look of realisation. She didn't understand what was happening here, who this stallion was or even what he was saying, but she could feel in her very soul that he meant harm to those she loved. And so, ever so slowly, her normally-happy face morphed into something else. Something angrier. Sombra began to notice this at last, arching an eyebrow as he looked on, unimpressed at the filly who now struggled in his grip.
"Ha! Don't bother, little one. No pony can escape my magic."
Flurry gurgled in a furious-sounding way, and just a second or two afterwards, her horn began to glow brightly. To this, Sombra actually felt some measure of amusement.
"Oh, that is simply precious! You think that little old you can actually hurt a stallion as powerful and mighty as King Somb-ARGH!!!"
Before he could even finish, a blast of magic was shot forth from the filly's horn, hitting him square in the chest and sending him flying backwards. He slammed right into the nearest wall, cracking it several times over, before finally slumping onto the ground. He gasped, clutching the spot on his chest where he'd been hit, before looking up with astonishment at the filly. Flurry herself spread out her wings to keep herself where she'd been floating before, albeit the right-way-up this time, with her horn still aglow, which she now pointed angrily to him.
"Ba! Babababoo!"
Sombra blinked.
"...Okay...not quite sure what happened there."
Getting to his hooves, he did his best to try and regain some dignity after that encounter.
"You have great strength, little alicorn, but you stand before the Master of Shadows! No filly, no matter how magically endowed, can withstand the-ARGH!!!"
Again, he was blasted, slamming into that same wall and causing even more cracks.
"Okay, what the actual Tartarus is going on here?!"
It was in that moment when the door of the chamber slammed open, and in charged Cadance and Shining. At first, they were horrified at the prospect their daughter being in danger, but within moments, as they took in the scenario, they slowly realised what was happening. Flurry was, of course, overjoyed to see her Mother and Father, and the parents themselves soon smirked as they looked down to the still-struggling Sombra.
"Well now, looks like the big bad Sombra's having a little trouble, my love," Cadance declared.
"Indeed, Cadance. Guess he's not all he's...cracked up to be?" Shining responded, pointing to the cracks on the wall where Sombra was leaning.
All eyes turned to him, dismayed by the pun, while Shining himself still tried to urge on a laugh from them.
"...Huh? Huh? Because of all the cracks?"
Cadance sighed, patting him on the shoulder.
"Shining, I love you with all my heart, but remember what we agreed? Just because you're a Dad doesn't mean you get to make Dad jokes."
Shining sighed.
"Yes, dear."
But Sombra, who had thoroughly had enough of this, finally crawled back to a standing position, pointing to the entire family.
"You may think you've won, usurpers! But you will never defeat the grea-ARGH!!!"
Another shot from Flurry, and the cracks deepened.
"Baboo!" Flurry declared.
"I DON'T KNOW WHAT THAT MEANS!!!" Sombra replied.
Another shot, this time sending his head slamming against the wall, leaving him groggy and disoriented.
"Mommy? Did you get the number of that Yak who drove into me?"
Another shot, and this time his senses, rather oddly, were knocked back into him.
"Okay, that's it! I demand that somepony tell me what in the wide-wide-world of Equestria is going on here! She's a toddler! A baby! How is she this much of a nuisance to me?!"
He stepped forward confidently, beating his chest with one hoof.
"I am Sombra! Lord of Crystals! Master of Shadows! Rightful despot of the Crystal Empire! I will not be cowed or humiliated by some mere child!"
Cadance, walking beside her still-very-powerful daughter, smiled innocently to her enemy.
"Oh? Because it seems to me like you are being humiliated by her."
Sombra snorted at her.
"Mock me all you wish, throne-stealer! But you dare not underestimate my power! Remember well, you stand before the very stallion whose great might was nearly strong enough to destroy the Crystal Heart itself!"
Shining pondered that, standing on the other side of Flurry from where Cadance was standing.
"Is that so? Well, here's a fun little bit of trivia for you..."
He gave Flurry a quick pat on the head.
"...meet the filly who actually destroyed it."
Sombra froze, his eyes slowly widening with realisation and shock, and as he did this, he looked from one pony to another, hoping immensely that they were joking. When it was clear that they were not, he simply sighed.
"Oh...Sugar Honey Iced Tea."
The last thing he saw was another blast from the world's tiniest alicorn, and all went dark.
Grogar watched, mouth agape, as his crystal ball revealed all that had happened. His fellow villains too watched in joint horror as their would-be ally no longer appeared in view. All they saw in those final moment was a shot from Flurry, and then boom, nothing. The crystal ball went silent, as did all of them, and after a full minute, the ancient goat cleared his throat, addressing his gathered allies.
"Well...let this be a lesson in the value of working together and..."
"Nope! I'm out!" Cozy Glow declared.
All turned to her as she continued.
"A baby beat Sombra...a friggin' baby! Screw this plan, just send me back to Tartarus already."
Tirek, though it pained him to do so, folded his arms and shrugged.
"Yeah, getting beaten once was bad enough, but facing them when I know a child could be my downfall? Yeah, there's no way I'd be able to live that down."
"You know, being defeated was no picnic, but at least I can be happy that it took literally every one of my enemies uniting to do it to me. I think I'll just go back to going crazy in the forest, thank you very much," Chrysalis added.
Grogar watched, dismayed that his plan was ending before it even had the chance to begin. Then, after staring down at his crystal ball for a while, he exhaled deeply.
"Maybe Celestia and Luna had the right idea. Because retirement is sounding pretty good right now."
Author's Note
Silly? Sure. Unlikely? Most definitely. But I'd have still been pretty entertained to see this be the way things went down 
Still a pretty fantastic episode as it was though. Great way to start the season 
