You are a simple construction pony. Your job consists of little more than digging up the ground so that the other workers can fill it in with cement. Then come the bricks and the wood, and eventually, more ponies. The town is expanding, and today you’re going to be digging up more dirt, just like you always do. As the giant shovel descends into the dirt for the one thousandth time, it hits something solid. Great, more rocks. Just what you need.
You uncover the rocks to find a large stone slab, perfectly level, with one small opening. The whole town becomes interested, and before long, your job is to uncover the entire site. A purple unicorn is now appointed to lead the excavation, and by the end of the day a staircase is revealed, descending into the gaping maw of the earth itself. Words are inscribed into the stone at the topmost stair in an ancient writing language, but the unicorn is able to read them aloud.
What lies beneath the earth in wait
for those who venture through the gate?
For those who dare to enter in
your days are quickly growing thin.
She descends the stairs with five other ponies, another unicorn, two earth ponies, and two pegasi. But why would they enter? The words were clearly a warning not to. After a few long minutes of listening to them examine the black of the chamber beneath, you hear a click, followed by a low rumbling sound. The earth begins to quake beneath your hooves. Everypony begins to run for cover, then stops, turns, and stares as the entranceway collapses on itself. Heavy rocks falling on the six ponies who are now trapped inside.
The shaking lasts for only a few minutes, but it might as well be an eternity. When it finally stops, you start up the machines, working to remove the boulders covering the stairway. A thundering roar rips through the air, causing everypony to freeze and listen to the screams now coming from beneath the earth. You return to your task, trying to get the machine to move the giant rocks, but as each one is moved, more shift into its place.
It takes all night, and most of the next day to clear the rocks away. The roars and screams have long since stopped, and what you find at the bottom of the stone staircase is not the chamber that should be there, but more earth and rock. The tunnel is gone, collapsed, and the six ponies who entered are gone.
Nopony tries to dig up the tunnel entrance. Some leave right away, some stay. You and the other workers take off your hats, observing a moment of silence. Everypony in town comes together later to hold a service for the six ponies. You spend the next week digging the foundation for the memorial that will be put up for them. Nopony ever speaks of the event again, but the monument in memory of the late unicorn and her friends, will never let you forget.
Nopony knew what lay beneath Ponyville. Nopony might ever know. And Nopony will dare to venture through the gate, where nopony knows what lies in wait.