Streams of brilliant moonlight filled the open field within the Celestial Gardens with a silver so intense it seemed as if it could be collected into pools and sprayed into the fountains that so filled the rest of the gardens. This area seemed different to Twilight Sparkle as she stepped out onto the short-cropped grass and trotted over to Princess Luna, who was standing next to a number of large buckets spread around the otherwise ordinary area.

“Greetings, Twilight Sparkle,” she called out. “I trust your discussion with my sister went well this eve, and that you are prepared to pick out your guards?”

“I told you before,” said Twilight, “I don’t need any guards in Ponyville. I may be a princess now, but Ponyville is a small town, and a bunch of armored guards would just get in the way.” She eyed the buckets sitting in a semicircle around Luna, their contents of small, white objects gleaming in the bright moonlight. “So, what are in the buckets, Princess Luna?”

“Why, your guards, of course.” Luna lifted a few of the white objects out of a nearby bucket and held them up for Twilight’s perusal.

“Teeth?” asked Twilight Sparkle, casting a skeptical eye at the nearly hoof-long sharp objects. “Those aren’t guards.”

“Dragon’s teeth, young one. ‘Tis the way we have ever created Royal Guards for the protection of our lands. We have an agreement with the dragons of the wastelands to collect their discarded young adult teeth, and in return, we provide considerable numbers of gemstones from our mines. It is quite a stable arrangement, and has been in place since ancient times.”

Twilight gave a small laugh. “Oh, that’s ripe. Good one, Your Highness.”

Luna reacted to the laugh with a slight frown, and a narrowing of her brows. “Wouldst thou think I would jape about such a serious subject?”

“No!” Twilight Sparkle took a step backwards with her wings unconsciously flaring out behind her. “It’s just… that’s silly, Princess Luna. I know the guards. I’ve talked to them. They have families.”

With a nod, Luna levitated out some smaller teeth out of another bucket. “Why of course, they do. It ‘twould be most cruel to deprive them of company of their own kind. The smaller infant dragon’s teeth form into quite believable young, and the female adolescent teeth make mares to complete their families.”

Taking Twilight’s astonished expression into account, Luna levitated out two larger teeth from a bucket and strode out into the field. “Your disbelief is obvious by thy expression, young princess. I believe it is correct to say that the proof is in the custard.”

Luna dug two small holes in the dense turf with her magic and dropped the teeth in, then trotted rather rapidly back over to where Twilight was fretting. She lifted her long horn to the night sky, and two beams of brilliant moonlight stabbed down onto the plain grass.

For the longest time, nothing happened.

Then there was a shifting of the ground, a faint hiccup as if a passing chipmunk had sneezed. A trembling around both patches of disturbed earth heaved up the grass, and a flash of white and gold was seen. Then two Royal Guards climbed up out of the raw earth, brushing off the loose dirt and coughing, with a few flaps of their ruffled wings to straighten the feathers.

“You see, Twilight Sparkle,” lectured Luna, seemingly oblivious to the stunned alicorn princess, “incisors are used to create pegasi, molars for earth ponies, and fangs for unicorns. A proper guard contingent for your new castle should be created from as close to identical teeth as possible, but you are in luck. The recent collection efforts among dragonkind have resulted in a plethora of teeth to choose from, and I believe we can match up a full contingent of guards for you that will be just as impressive as the ones we have here in Canterlot.”

“No! No, this can’t be!” said Twilight, pacing back and forth while twitching her wings. “I know they’re all alike in so many ways, but I always thought that was from the armor and the training and… Teeth? How can they be teeth? My brother was a Royal Guard!”

“Oh, yes!” said Luna, reaching into a different bucket and pulling out a huge fang nearly four hooves long. “We have several from that particular dragon. I have held one back for my consort when I have a few centuries to properly train him, but if you wish, you could have this one. He’s a strong unicorn, from the looks of him, and he should serve you well as consort, much as Princess mi Amore Cadenza had claimed hers just before your birth. Admittedly, he may take quite a bit of training in the early years before he can share your bed, but—”

Whatever Luna was about to say was cut off as Twilight Sparkle bolted, wings and hooves flying in all directions as she galloped off towards the castle with a loud cry of, “Princess Celestia!! Princess Celestia!!”

Luna stood in the moonlight, a faint smile crossing her face as the two somewhat dirty Royal Guards approached. “Is that it?” asked the first one.

“Yes, thank you. Your assistance is greatly appreciated. Princess Twilight Sparkle is young and impressionable, and believes far too much what she is told. This day of pranking and jests is indeed a great thing, allowing us to enlighten her to the ways of an alicorn as well as being great fun.” She turned to the guards with a twinkle in her eye. “Did you gentlecolts enjoy your part in our little humorous deception?”

“Yes Ma’am,” said the first guard. “I thought I might suffocate out there underground for a little bit, but your spell worked just the way you said.” A small smile crept onto his face and he continued, “You may consider doing that to the incoming Academy cadet class next year. I’d be more than happy to assist in any way possible.”

“I dont’ know,” said the second guard with just the least bit of a frown. “It was funny, I’ll admit, but where did Princess Twilight Sparkle go?”

“To my sister, of course,” said Princess Luna. “I timed this so that she should have just laid down and turned out the light when Twilight shows up.

“And that, dear sister, is why you don’t take the last piece of cake at dinner,” said Luna, nearly under her breath.

“Very nice,” said the second guard, “but what’s going to happen once Princess Twilight Sparkle tells Princess Celestia about the dragon’s teeth?”

The three of them turned slightly and looked up into the sky at the Royal Towers, and in particular one large, well-lit window with a sun symbol above it that had just gone dark.

There was a flash of blinding violet light that lit the window.

A somewhat flickering glow as the lamp was turned back on.

And then a voice, which unmistakably belonged to the Princess of the Sun.

OUR GUARDS ARE WHAT, TWILIGHT?!

Princess Luna smiled wider. “Celestia will tell her the tooth, of course.”