Nothing Can Be Worse Than That Hundred-Tailed Cat.
"Hahahahahahaaa!" The demonic Sunset Shimmer laughed as she floated over the defeated Mane Six. They weren't dead, they just had their flanks kicked by someone who had a lot more experience being a fighting human that knew martial arts. That, and she'd seen enough Dragonball Z and played enough dodgeball to know when she needed to DOOODGE a big glowing energy attack. She even prepared for this day for years by playing Touhou and other Bullet Hell games when she wasn't at school. Her foes hadn't stood (Heh heh) a chance. Oh, sweet Celestia, that was brilliant. That was so going in her journal.
"Now, my dark army! ATTAAACK!!!" Sunset Shimmer laughed, pointing at the portal, the base of that statue. It was big enough for maybe three people to get through at once at the most, but that wouldn't stop her. Her army converged upon the portal, slowly walking in and pushing each other as they all poured through the portal like grains poured into a sink.
And in Equestria, the Mane Six and Celestia watched in horror as the mind-controlled zombies - practically brain-dead, were unaffected by the mind-numbing blackout-causing pain that was poorly-cast interdimensional travel - came through the portal, and fell over, not used to moving around on four equally-long legs. They shakily got up, and most of the Equestrian ponies in the room were now terrified.
Most of them. Celestia's horn began to glow and Rainbow Dash flared out her wings, and Pinkie grabbed her Party Cannon from somewhere out of everypony's field of vision, and then...
There was a loud and hollow "Donk" sound as a large metal cube slammed itself down onto their heads, and then rose back up slowly as a rectangle shaped similarly to the front of a human's bulldozer came from the right, pushing them off to the left side of the room as more mind-controlled zombie teenagers suddenly turned into ponies came through the portal, only to get knocked out by that large metal cube, and swept to the right side of the large room as the flow of walking targets continued.
"This... This actually works." Silver said in amused disbelief as everypony turned to look at him in surprise, the silver Unicorn giving his metal objects the continuous command to keep doing what they were doing so he could sit back and watch the show. "She's got an army of strange creatures controlled by dark magic, they turn into ordinary ponies as soon as they trot into our world, and... she's got them stumbling through a small tactical bottleneck in the form of a small portal. Right into this castle's basement floor, where five out of six of the Element Bearers, plus myself, Princess Celestia, and as many Royal Guards as Celestia wants can easily take them out and toss them back into the portal if need be. It's... it's like she's never read a book on tactics in her whole life. What an absolute idiot."
Pinkie Pie burst into laughter, and Rainbow started to join in once she realized there was no danger here.
"Silver Star?" Princess Celestia asked calmly. "I will admit she may have fallen a long way, but she was once one of my greatest pupils."
"Oh. I'll be nice and assume it was due to incredible magic power, or maybe she hyperspecializes in fields that have nothing to do with tactics, planning, or basic logic." Silver said, summoning a big, juicy apple enchanted to taste like a marshmallow with strawberry jam inside it into his raised hoof, taking a bite out of it, the apple and strawberry jam regenerating in his hoof as he chewed. "Or maybe she just assumed we'd be so terrified, we'd lose our minds and forget how to use magic and get overrun by these... how old /are/ these imvaders? Anyway, let's recap on exactly what she's doing here... she's gone to a world beyond our own, and gathered an army of followers. A place where there are lots of people in one place... I'll be kind and assume it's somewhere like a school for immensely powerful, strong, or intelligent beings, whatever these beings once were. They'd have to have some strangely nonstandard design to have trouble walking on four legs, and they walked through here on two, so maybe they're some kind of bipedal squid monsters. Great idea, very impressive on paper... if you fold the paper up into a paper hat, look at only one side, and use paint to black out all of the stupid parts still visible. And even then, what would her plan be if you removed the stupid parts? Would it just be the word 'The' a few times on an otherwise-completely-blacked-out page? Any strategic advantage having monsters like those on your side is negated when the portal turns them into ordinary ponies the second they enter this world. Furthermore, there are only two strategic advantages they could really take advantage of in their pony forms: Greater numbers, and intelligence. But she's got them all mind-controlled, and it's a VERY clumsy brute-force job, so they can't think of anything beyond 'Do as mistress commands', like the lowest form of Changeling. As for numbers, they're heading through one really bad bottleneck, so they cannot properly apply pressure or swarm us, so all we have to do to beat them is... this, really."
The ponies gathered continued to watch as the cube came down and knocked out invading ponies and rose back up as they were swept away by his second metal object, like the windscreen wipers on the glass windscreen of an airship but better and strangely funny.
"Hey, wasn't a bottleneck what the Spanthers did when they fought the Purrsians in 300?" Rainbow Dash wondered.
"Eeeyes." Silver said. "It would probably be a lot cooler, but nowhere near as safe, if we grabbed some armour and fought the invaders in an epic pony war. But... this is kinda funny. I think I might use the Infuse Life spell on that Cube, name him Cubey, give him eyes and a mouth and a decorative tesselating fractal pattern, and see if he can make this more fun."
"It's just a cube." Rarity pointed out.
"His name is now Cubey." Silver said, grinning, and his horn glowed blue as he cast the spell.
"Wheeee!" Cubey called out as he slammed himself down onto the invaders, just in time for the sweeper to sweep them away. "Woah, look at the edges on that one!" Cubey said, staring at the sweeper with adoration in his eyes.
"Perhaps the beings of this world have weaponry, incredibly advanced weaponry that can obliterate planets and moons?" Silver offered hopefully. "Going through the portal wouldn't help them much, though, since clothing and such is altered when they arrive, to be seen as standard in our world. Such items would likely turn into nonmagical bows or swords or something."
"Maybe." Rainbow shrugged.
"Princess Celestia, what do you know of this world?" Silver asked.
"Well... you may have overestimated it. Their weapons are powerful, but they cannot be brought through this portal. Their people may be strong, but as you say, they aren't used to moving on four legs. They aren't Squids, either, they're more... Imagine a chimp, stretched out and averaging just below six feet tall, with a 30% chance of having a brilliant mind, even by our standards, and a 70% chance of having nothing to write home about. As for the location... I fear she has gone to a high school."
"A school for high intellects?" Silver guessed.
"Yeeehaaw!" Cubey yelled, knocking out another wave of invaders. He then blushed visibly, with darker grey patches forming on his metal face. "Sorry, I'm never saying that again."
"The school that deals in the second stage of education. Then there is a third, but only the second and third actually have an effect on the person's life."
"What a terrible design." Silver said. "If so much time is spent on schooling... is each human like a team of scientists in one?"
"No. Personally, I think our system of a well-rounded education in everything at a young age followed by specific training in what your Cutie Mark predestines, with the option of gaining additional skills later in life is far better suited to our world. But they have no Cutie Marks, so they are forced to wait until the ages of approximately sixteen before they can choose their path in life."
"Choose? Please tell me there's at least some kind of aptitude test involved." Silver said, fully expecting the worst.
"Rarely." She admitted.
Silver's face met his hoof. "So somepony like Sweetie Belle or Caramel could willingly choose to be a doctor, and after nothing besides some human schooling, people's lives would be in their hooves? What on earth could Sunset Shimmer possibly have to gain from such an awful world?" Silver wondered.
"Touchdown!" Cubey called out, slamming himself down onto the heads of the invaders. "And the crowd goes wild!" He yelled, and exhaled loudly to imitate the sound of a crowd cheering.
"So, since these glorified lemmings keep coming in, what shall we do? Shall I pelt the other world with large and fast-moving metal boulders through this portal? Inanimate objects can't be changed, I assume, provided they are not clothes or tools that fit a residual self image, I remember that coming up often in regards to interdimensional travel. Or shall I make or find a large and very deep pit or prison or spi- a pit filled with jelly, and have the portal lead straight into a portal of my or Princess Celestia's creation that spits the invaders in the pit?"
"Sounds reasonable." Princess Celestia admitted.
"Alternatively, we could have Princess Luna move the moon about or use time spells - depends on whether the moon is connected to the portal, or if the number of moons is coincidental and it instead has a time limit - to make this portal suddenly run out of time and close, though this would trap Twilight in there for the short amount of time it'd take for us to get a biologically-modified rescue team trained in bipedal movement and combat, send them in, and watch them come back out with Twilight as we toss in nets filled with downed invaders. Or I could use metal walls to shove them all back in, then put a metal wall in front of the mirror and see what happens, maybe cover it in a metal dome to plug up the hole and prevent any more coming in until Twilight's ready to come home. I'm liking the 'Send in the rescue team' idea. Sure, you said bad things happen if too many people enter a dimension they aren't supposed to enter at once, but they've sent in at least fifty invaders right now, so they're clearly not playing by our rules, and we need to stop her before she damages the stability of this universe or theirs any more. And they'll keep sending more in until they run out of people, which may never happen in our lifetimes if the rumours about humans are true, or until we send in a team to defeat Sunset Shimmer, grab Twilight, get her Element of Harmony back, and seal this portal up. For that, we can use either a time-stop shell maintained by a magical item, or a small metal dome positioned so that the mirror is at the bottom facing up, causing anyone who enters to go in, hop up through the portal and appear here, find nothing but solid darkness and creepy echoes, and fall back into the portal so they end up back in their own world, convinced to never try that again. Furthermore, reflections can only be made in light, so this may also completely deactivate and separate the two worlds. By the way, Princess Celestia, I know a really nice pony who can make really great glass and gem sculptures, I'm sure she would be able to make some nice glass cages or containers or cases for these or any other artefacts."
"That will do nicely." Princess Celestia said. "Silver... That is quite brilliant."
Normally, Silver would have graciously accepted a compliment like this, but this came from Princess Celestia, and so he squeed like a foal.
"Bonk!" Cubey shouted. "Don't worry, I've got it all under control over here! They're not getting through while I'm around! Hey, so... Master? When are you going to do that pattern thing? I want to look cooler."
"Rarity, would you like to do the honours?" Silver offered.
"Oh, no, I couldn't." Rarity said, uncertain as to how she'd make a simple cube look cooler.
Silver nodded, and parts of Cubey's metal body changed colour, his black-dot eyes turning blue as his edges became lined with gold, a bronze zigzag pattern framing the edges as gold circles surrounding silver dots appeared on the zigzag pattern on opposite sides of the point each time. Finally, his face was framed by a gold square two inches thick, a thin bronze square outlining its edges. And finally, the bottom became a bright sky blue, much like the cloudless sky outside, and the top side became enchanted to exactly copy whatever was beneath it, and then the top side gained the ability to copy what was beneath it or display whatever it wanted to show.
"Cool!" Rainbow said.
"It does look rather nice." Rarity admitted.
"WOOHOOOOO!" Cubey yelled happily, coming down for another attack on the invaders. "Um... Princess Celestia, right?" He asked.
"Yes?" Princess Celestia asked kindly.
/Two hours later/
"And so, for your great service to Equestria in its hour of need..." Princess Celestia said in front of the mind-bendingly large crowd of ponies gathered in her new award-giving room, which was even bigger than it was last time Silver was here.
"I grant you this medal." Princess Celestia said, nodding once, which was the signal for the royal medal-givers to appear and place one medal on Silver Star's graciously-bowed head, and another was held up to Cubey, the pink royal medal-giver assigned to him uncertainly looking at the big metal cube that dwarfed him in size. Cubey's blue tongue then shot out like a frog's, grabbing and swallowing the medal, and as he smiled, the medal reappeared on his body, permanently embedded in his front, a few inches below his mouth.
"This is the happiest day of my li-hi-hi:-hiiife!" Cubey declared, silver tears welling up in his eyes.
"Furthermore... Cubey, would you like to join the Royal Guard?" Princess Celestia asked.
"YES!" Cubey squealed with happiness as he hopped up into the air and gleefully spun around in the air. "Yes yes yes yes yes yes YES!"
"They grow up so fast!" Silver said like a proud and overjoyed parent.
Meanwhile, on Earth...
"What do you mean, the portal has stopped working properly?!" Sunset Shimmer demanded from one of her mind-controlled zombie slaves. "It's bad enough that Twilight escaped with my crown half an hour ago when a bunch of metal balls were fired out, covering those armourclad fighters that came out of the portal and grabbed them both after hitting me with a golden torch with an orange gemstone enchanted to fire antimagic rays. Now you're telling me we can't get EITHER of those things back?!"
"Yesss... mistress..." The teenaged boy droned mindlessly.
Sunset Shimmer threw her clenched fists outwards and screamed in fury, doomed to forever be surrounded by the meaningless and hollow obedience of slaves who lack the brainpower to think for themselves, just as the her she had become had always wanted, yet unable to get revenge on Equestria or ever go back home again. What stung the most was that this was partly what she wanted, and why she chose to go to a world without magic, but it was always as a stepping stone to her greatee victory, not the end goal... right? Sure, she'd spent so many years basking in the false love of her people, but...
She realized what she had done wrong, and now, there was no way to fix it.
She fell to her knees, threw her head back, raised her hands to the sky, and yelled, "NOOOOOOOOOOOOOOOOOOoooooooooooo..."
In one week, when an emissary of Equestria came to take the broken Sunset Shimmer back to Equestria, she accepted, even if she had semi-conquered most of the town out of boredom using her army of brainless zombies, who were given their cures once she had left.
