Pickaxe after pickaxe slowely breaks away the stone just to reveal a harder chalk like stone. Each strike making a louder clang than the previous. The earth ponys and unicorns down the deep mine swing their tools faster and faster as they edge ever more into the strange stone, ever hopping to find what they had been hired to mine so many months before. For this is a crystal mine, one of the most successfull crystal mines in all equestria! Due to its unique location they dont have to work so hard to reveal the crystal hidden by the soft stone. That is until today. Today they came across a large cavern surrounded by the most resistent stone they have ever seen or heard of.this type of stone was used to build canterlot aswell as some of the ruined castle of the royal sisters in the everfree forest.

A pickaxe slices straight through a fin layer of the rock and light beams through revealing a small amount of rusted metal. Together they make the whole large enough for a singular pony to enter at a time. Walking around the large lump of slightly rusted metal the unicorns use their magic to reveal a titanic metal spider like structure filling the cavern, but as an earth pony miner goes to touch it smoke starts billowing out the top of a small chimney on top of the torso of the spider like mound of metal. The miners stand back, mouths agape as the structure shudders then moves. Turning so the front faces the group of ponies.
the cavern is suddenly filled with the sound of mechanical laughter when the front of the machi e bends down to get a closer look at the ponies.
the sound of metal sliding against metal is heard causing the ponies so cover their ears to try and block out the sound. They dont seam to notice the weapon being lowered out the underneath of the head of the mechanical beast until its too late. Their agonising screams are only drowned out the the fire that is spewed down upon them. After the ponies are dead the flame thrower is brought back inton the head leaving only card remains to show it was ever there.
hearing the screams of pain the mine owner sends down a pagasus with a blue mane and orange coat to find out what the screaming was about. Even when flying it takes her a good half an hour before she arives at the opening and sees the chard remains of her coleagues and the large mass of metal. Screaming herself she flies as fast as she can back to the surface where she quickly explains what it is she saw. She talks about the chared bodies and about the hulk of metal that seemed to be moving. Soon after she starts hyperventelating before she passes out.
Before he can give out any orders the mine owner aswell as the rest of the miners hear a high pitch almost squeeking sound before the whole mine is filled with dust and a loud whiring sound. The amount of heat comming from the cave melting some of the rock around the enterance way. As the dust clears a large beam of light blue is revealed making the whole mine five times the size it was previously.

the final court of the day nearing its end celestia and luna gaze out the window and their eyes widen in shock. In the distance a huge almost pillar like beam of sky blue is shooting straight into the sky from a dust cloud that could hide canterlot. The two princess's share a look that says. 'Thats not good'
"This court is now suspended until a later date!" Celestia states loudly causing the room to empty and the guards to look questionablyat her.
A scroll apears infront of celestia and she quickly writes a letter to her favroite student and fellow princess, twilight sparkle. She sends it off and heads towards the throne room. This is clearly troubling her.

The sound of heavy metal crushing stone eminates from deep within the mine as the beem dissapates leaving all who stared at it near the mine seeing stars. The ground start shaking with each step as the mechanical erachnid climbs towards the surface. Each step sending rocks tumbling down past it. Each step drawing it that much closer to the surface.
"And the damned alicorns thought they had trappec me forever! Ha! They only delayed their own demise!" The machine says in a clearly angered tone.

Outside the mine they hear what the machine says over the sound of it drawing closer, each steo sounding like thunder in their ears. Smoke starts pouring from the mouth of the mine a a giant metal limb smashes a 'warning! Possible rock slides!' Sign at the enterance. As the machine rises to its full height outside the mine it spots the small group of miners cowering while staring up at him. The machine being larger than their tallest building they attempt to run and scatter to no avail. Fire floods the minning town filling it with the screams of the dying.
after this only one pony remains. A pegasus with blue maned pegasus who is now covered with ash and burns.
"You! Why would you do this!?" She yells at the machine.
"I will explain myself if you inform youre rulers, that promeathius has returned!" The machine replys sounding almost joyfull.
"S, s, so why d, d, did you have t t t to kill th, them!? Y, you monster!" She yells at him.
"REVENGE!" the mechanical arachnid shouts before aiming its weapon at her. "Just go. Its been fun. Dont come back." The machine says bluntly.
yelping she flies as fast as she can towards canterlot. Not realising that shes revealing the location of the princesses. Aswell as equestrias capital city.

The doors to the throne room swing open as twilight and her friends enter to find a woried looking luna and celestia. Twilight seing this straight away rushes towards celestia and says. "Princess celestia! Princess luna! Whats wrong!?"
"Twilight, something, has been found in soft rock crystal mine. I fear the worst has happened. I need you and youre friends to find out what happened." celestia says.
"Where is the mine? What do you mean you fear the worst!" Twilight says with a look of confusion plastered on her face.
"Twilight, we fear that the mining town maybe no more. It is or was 2 miles north from here. Were relying on you and youre friends twilight." Luna says.
the doors fly open a second time. Except this time a badly burnt pegasus flies through in clear panic.
"Princess celestia! Soft rock mine! Every pony dead! Living metal!" At that the pegasus collapses to the floor. Worn out after flying for 2 miles as fast as she could with no brakes.
shes picked up in lunas magic glow and luna says "what news does thou bring of soft romck mine!"
"Princess luna, it came out of the mine. It said something about being stuck there by alicorns. Then it destroyed the town and everpony who lived there. I barely escaped with my life!" she says as exhaustion takes her to a deep sleep.

Trees and animals are crushed and destroyed as the machine makes its way ti the nearest settlement to continue its slaughter. Leaving a trail of deastruction in its wake.

Author's Notes:

I have not had this proof read so any way I can improve apon this is welcome.