"Surprise!"
"Wh- No, wait!" His warning came too late. The white-and-blue blur had barrelled into the room without notice and the stool had no chance. Getting trampled and hurled across the room was a high price to pay for being in front of the door at the wrong moment. He sighed heavily as the stool's former occupants, consisting of three-hundred-odd carefully stacked pages of notes, fluttered around his head. The blur shakily stood up, rubbing its head. "Great, are you happy now? Those took all morning to sort."
"Aww, I'm sorry Bee," the blur said, eyes downcast. "You've been in here for so long I wanted to see if you were asleep or... something..." She trailed off as she saw the devastated pile of notes strewn about the room. "Why did you even have that in front of the door? That was very silly of you, somepony could have hurt themselves!"
He knelt down and patted her head with his hoof. "Well at least they didn't eh?" He couldn't stay angry for long, not with that innocent, fun-loving little face staring up at him. "C'mon, help me get this cleared up. It'll be much quicker with your help."
"You're not angry?" She gasped as she clutched his foreleg, beaming from ear to ear.
"Of course not," he chuckled, "it was my fault, absolutely. Now how about helping me clear this mess up?"
"Allow me!" she squealed. The stool incident had ruffled her mane into an unsightly mess, but with a toss of her head, a shiny white horn was revealed. Her brow furrowed slightly as the horn glowed. Suddenly every stray page was lifted off the floor, causing a great rustling din. She winced.
"Steady on, Sky! I'd like these pages in one piece, please," Bee laughed as he retrieved the stool. With renewed determination to make up for her clumsiness, Sky floated the pages towards her and began sorting them by number. Her big brother watched as the pages danced around each other. His little sister's eyes flicked back and forth, reading the page numbers. Her horn continued to glow as the paper quickly filed itself into a neat stack.
"Er, Bee, would you mind taking this pile I've done so far?" She gently floated a thick stack towards him. "It's easier if I do it in bits and pieces." He gingerly caught the stack of paper as it wafted past.
"Take your time, it took me half a day to sort that lot out, there's no need for you to rush through it in three minutes." He carefully eyed how she manipulated the paper in the air around her head. Scattered sheets were methodically being grouped by general page number, before being further sorted into correct order. She has much more control over delicate magic than she used to, Bee thought to himself. She'll get there in the end.
The rest of the afternoon passed without much ado. The denizens of Canterlot went about their business far below Bee's study, perched near the top of Celestia's School for Gifted Unicorns. He wasn't actually a unicorn, but as an official researcher working under the auspices of Princess Celestia herself, he was granted accommodation at the School. His sister was also permitted to live there, of course. She didn’t usually bother him that much, what with her private lessons with the Princess taking up most of her days and all.
For many years the Princess had taught her own personal protégé in the form of a very gifted unicorn filly named Twilight Sparkle, but as the filly grew into a young mare, the Princess wondered if any other truly exceptional foals had undiscovered potential, which required focused study to unlock.
Then Bee arrived on the scene with Sky in tow.
His actual name was Wonderwhy, but his very distinctive and very striking black-and-yellow coat, mane and tail quickly earned him the nickname 'Bee' among anypony who got to know him. His colours weren't the only unusual things about his appearance, however. He was huge, with a thickset body supported by powerful muscle, and he stood taller than everypony else he knew except the Princess, with whom he stood eye-to-eye. As a pegasus he had wings, but they too were unusual. Apart from being predictably sizeable, they were not feathery as one would expect, but tough and leathery. More like dragon wings.
Wonderwhy's incredible enthusiasm for learning anything and everything about anything and everything, along with his noteworthy appearance, quickly caught the attention of Princess Celestia who was in need of somepony to help keep her informed and up-to-date on happenings in Equestria. Her interest was also piqued by Bee's appearance, but despite several years of research between the two of them, they failed to find any solid information about Bee's ancestors.
"They had reason to lie low it seems," he would often remark after chasing down yet another red herring. His current family was just as clueless.
Whatever unique bloodline ran through Bee, however, had a far more profound effect on his sister.
Brightlight Bluesky, or Brightsky for short and Sky for even shorter, was a sweet little thing that had a surprisingly tough side when the situation required it. Her normally unkempt mane shielded her white horn most of the time. Nothing is unusual about a unicorn filly, so initially Celestia had no reason to think her anything important.
That changed very quickly once she got on less formal terms with Bee, and he spoke more openly about his sister. Very few ponies knew her special secret, and she kept it well hidden under a starry red-and-white cloak which she loved very much. Maybe everypony would accept her as she was, but her family wanted to keep her 'special condition' under wraps, both literally and figuratively, until they knew just what it meant for the little filly's future.
Once Twilight had matured enough to be more independent of the Princess with her studies, Sky was offered the role of personal protégé too. So far she hadn't managed to perform any magical feats of any significance. During her entrance exam for the School, by contrast, Twilight had hatched a dragon egg, making the baby instantly grow to a ridiculous size, while also levitating the examiners and transforming her parents into plants.
Celestia was able to repair the damage, but so far such a need hadn't arisen with Sky. Which was a good thing in a way, but Bee and the Princess couldn’t help but wonder what was going on inside Sky's little body. She already had her cutie mark; she had obtained it while aimlessly stargazing one night, which was another surprise. Cutie marks normally appear after some noteworthy event, not just out of the blue.
Whatever mystery surrounded Brightsky, Wonderwhy and Princess Celestia felt sure that one day all would be revealed and she would be mysterious no more. Celestia hoped to be present when the filly's unseen magical power finally surfaced, not only out of curiosity, but to safeguard Brightsky and everything around her from whatever accidental havoc she could cause.
This might sound over-the-top. After all, Sky was just another unicorn foal, right? Except she wasn't. If you ever caught a glimpse of her back beneath her cloak, you would see two little feathery wings, as white and as fluffy as the clouds they enabled her to walk on.
Brightlight Bluesky, little sister of towering dragon-winged Wonderwhy, was a pegasus unicorn.
An alicorn.