Disclaimer: My Little Pony Friendship is Magic is owned by Hasbro. Halo is owned by Microsoft (or some sub-company thereof). I have no stake in either and seek no profit from this work. This is purely a fan creation.
17 September 2551 0258 Military standard time
Location: Slipspace, En Route to Reach from [CLASSIFIED]
It was, more or less, business as usual aboard the Guam. Most of the crew of the kilometer-and-a-half-long cruiser was in croysleep. After all, they were still a week from their destination, even at the faster than light speeds provided by slipspace travel and during the trip there was little to do besides sleep anyway. With the ship's AI handling most, if not all, of the "steering", even the skeleton crew kept awake in case of emergency found themselves bored more often than not, Which inevitably lead to speculation on their task.
The ONI briefing was nothing more than a set of instructions: go to the coordinates they were not allowed to know, pick up a package they were not allowed to open from an installation whose name and location they were not allowed to know, and return home. There was even a spook on board to make sure they follow it to the letter. He more or less sulked on the bridge the whole time. The main question going around the ship was 'why us?' Cruisers like the Guam were in very short supply and very high demand for the war effort. With the Covenant steamrolling their way through fleets and colonies, everything was in high demand, but the Guam was one of, if not the largest and most well-armed ships left, and a frigate could have done this job.
Well, wondering won't get me any answers, mused Captain Arnold, whose fine ship this was. Hell, they'll probably just give me some shore leave and say it never happened. It wouldn't be the first time someone got pulled from the front lines to run errands for some ONI pet-project. He was on the observation deck at the moment, staring out at the infinite blackness of slipspace. He often came here to think, the blank void offering not so much as a twinkling star to distract his wandering mind.
It was as the captain was leaving to glare at the package through a security camera's feed for what seemed like the hundredth time, that it happened. Warning lights flashed, followed barely a second later by a blinding light and searing pain as it felt like his body was being torn asunder.
For the ship's AI Agatha, those brief seconds felt like years. It started with an anomaly in the cargo hold, the ONI crate to be precise. Almost before she could react, which is impressive when one thinks as fast as most supercomputers, some… force tried to hijack the ships FTL drive and drag them out of slipspace on some bizarre new heading. Luckily for everyone, she had managed to isolate the package's interfering frequency and stop the unexpected detour before it could do more than budge the ship out of place slightly. Such a sudden translation to real space would have torn the ship and everyone on it to shreds.
Unfortunately, the slight brush with wherever it was trying to send them had created its own anomaly, one far more immediately noticeable, and with far stranger effects.
Theodore 'Ted' Hathings, the ships communications officer, was in the mess hall, playing poker with other members of the bridge crew when the Flash hit. It was over before he could react, the pain gone before he could scream. When the light faded, he was on the floor, though he didn't remember falling, and his entire body felt strange, as if he hadn't spent his entire life living in it. He slowly extracted himself from the floor, having trouble making his body move the way it was supposed to. Everything just felt wrong.
When he got his head back up to table level, he froze. Staring back at him was something that was obviously not human. In fact, it looked like a small horse or pony with abnormally large eyes, a pale yellow coat of fur, and a single horn spiraled out of the center of its forehead. As it caught sight of him, it too froze. As they stared at each other, other ponies began rising from their positions on the floor. Most had horns as well, though one had a pair of wings instead, all of them were different colors, and each had a mark on its rear end which somehow represented the person who had occupied that seat moments before.
He was so busy glancing from one pony to another that he almost didn't notice they looked almost as freaked out as he was. In fact, he was about to panic right there when one of them walked rather unsteadily to the table and looked at the cards strewn about. Ted followed his gaze and noticed that there were no less than seven aces lying amongst the pile. "Well, so much for that hand," he said, sounding rather disappointed that their game was interrupted in such a manner.
"Who cares about the game?" one of the other apparent-crewmen shouted. "We don't even have hand anymore!"
"Calm down! I was just trying to lighten the mood."
"We're in the middle of a crisis! We don't need a lighter mood! If we needed a lighter mood, I'd get out my unicycle and start doing laps around the gymnasium!"
"You have a unicycle?" one of the other, non-panicking people present asked.
"That's not the point! The point is that our survival on this ship is dependent on us pushing buttons, and our hooves are now five times the size of the buttons we need to push! If anything, anything at all goes wrong, we! Are going! To die!" By this point he was practically frothing at the mouth, and several other crewmen/crewponies were looking worried as well.
The fearful tension lessened somewhat when a nearby comms speaker crackled noisily to life, startling the unintentional panic-monger into leaping several feet into the air and landing flat on his back, legs flailing in a myriad of directions. "All active crew please report to the bridge. As you may have noticed, we have a major situation," the captain's voice sounded from the offending speaker.
"See? Even the captain doesn't think it's a crisis," the pony who had first spoken said with a haughty tone, earning an annoyed "shut up," from the form sprawled on the floor.
As the group headed to the ship's bridge, they occasionally met up with other crew members making their way there as well. Most of them looked kind of shell-shocked, as though they hadn't quite accepted what had just happened. I can't really blame them, Ted thought to himself. I'm having a hard time believing this myself.
"So, what the hell do you think just happened?" said one of the newer arrivals, a dark purple unicorn who, judging from the twin gears adorning his rump, worked in engineering. "I mean, is this some sort of new Covie weapon? Because if it is, we are so hosed."
"Nah," replied Nathan, the ship's navigations officer. "The Covenant aren't that subtle. They would've just blasted the ship and moved on. My money's on that box we picked up. I only got to see it once, but that was enough to get some weird vibes from it."
"So this is ONI's fault? Well, so much for going home any time soon."
"Hey, shut it! We're here."
The group entered the bridge, crowded despite the fact that most of the crew was still frozen. As Ted looked around, he noticed that, while most of the crewpeople present were unicorns, some of them were winged pegasi, and a few had neither wings nor a horn. The captain, light brown 'generic' pony with a waving UNSC flag on his rear, was standing at the head of the gathering, conversing quietly with Agatha, who seemed unchanged, and the ONI spook, who now sported a horn, and a mark resembling the emblem of the Office of Naval Intelligence on his rump like some sort of brand.
As the last of the ponified people filed into the bridge, the captain spoke up. "As you have no doubt noticed, we are no longer human. Thanks to Agatha's sensor readings during the event and the input of Mr. Smith here, we have come up with a good guess as to what just happened. The package we picked up was supposedly some kind of Forerunner artifact, a battery of immense power, to be precise."
"So it just up and decided to turn us all into ponies?" one of the small crowd spoke up.
"No." this time it was Agatha who spoke, her hologram, a blonde woman with a practical Victorian era outfit, dissipating to make way for a diagram of the ship with the Slipspace drive and offending crate highlighted in red. "Your condition is merely a side effect of the objects attempt to hijack out FTL drive and yank us off course. If it had succeeded, none of you would be worrying about your bodies."
"So why would that turn us into ponies?"
"I honestly have no idea," the AI replied. "All I managed to get from the attempt was a set of coordinates, but I have no idea where they would lead."
"Did it get the people in cryo?"
"Did it do anything else?"
"Aside from reshaping any clothing worn at the time, no, which means we are effectively unarmed at the moment.
"So how come Agg didn't change?"
"Because," the AI spoke up, "my hologram is just a projection which I can change at any time. Even if it did end up getting affected, I could change it back before you could blink."
"Any other questions?" Silence filled the bridge for a moment. "Good. We'll be arriving at Reach in a week, and I won't have anyone tripping over their own feet when we get there. So start waking people up and getting them acclimated. Hop to it people!"
Meanwhile, in the peaceful land of Equestria, the two princesses who ruled over its pony inhabitants with millennia of wisdom and god-like power were having a very confused discussion.
"Are you sure that's what you felt?" Princess Luna was somewhat smaller than her sister, though still taller than almost any other living pony. Her coat was dark blue, almost black, and her mane and tale were not so much hair as a starry night drifting from her body, seemingly blown by some invisible wind. She, like her sister, had both wings and a horn, and she used her magic to bring beautiful nights to their kingdom, as represented by the crescent moon cutie mark adorning her flank.
"Yes Luna. The Elements of Harmony are not the kind thing you can forget." Princess Celestia was a radiant white in color, with a flowing "mane" the colors of the sunrise. Her appearance, along with the sun emblazoned upon her flank, made it clear that she was In charge of the daytime. "And yes, all six elements are right where I left them. I checked as soon as I could."
"But it's been nearly ten thousand years since we found them! Why would a new one wait until now to reveal itself?"
"I don't know, Luna. Perhaps it has something to do with them being used in such rapid succession. It was ten thousand years ago that we used them to imprison Discord. A thousand years since I used them to… to imprison you." Luna flinched at the mention of her brief stint as Nightmare Moon, and subsequent thousand year banishment to the moon. Even now, after more than a year with the best therapists in Equestria, she was having trouble dealing with that particular personal demon. "And now they've been used twice in less than a year, on you and Discord both!"
"If that were the case, then why would it leave? And you said you felt other presences with it, like normal ponies but not quite. What would that mean?"
"I don't know, but I fear there are circumstances at work here that we could not possibly know. Please tell me if you find anything strange while you're out at night, and be safe. I don't want to lose you again."
"Don't worry Tia, I will." At that, the two princesses left. After all, it was almost sunset, and they both had jobs to do.
Authors notes: This was pounded out in approximately eight hours, so little errors may have slipped through. I feel good about this though. Being turned into a pony and being stuck in Equestria seem to go hand in hand, but I've decided to shake that up and see what the military minds of the UNSC think about this without bringing magic into the mix.
And no, the Elements of Harmony are not Forerunner artifacts. They are much older and more mysterious, in addition to not being native to the Halo Universe.
Post-Revision Note: Looking back, I noticed that the atmosphere aboard the Guam was a lot less strict than one would expect from a military vessel, so I performed a near-complete overhaul of the chapter. This took approximately an hour, and was done in the middle of the night, so please let me know if anything is amiss.