Ezzin

The first pony I named Abandon Hope, her real name was just Hope until the fateful day when she lost her friend named Candlelight.

They were both archaeologists and they were looking for all sorts of artifacts all over Equestria, tomb raiders so to speak.

One day they got to a huge castle half buried underground (ref - Brenenburg Castle from Amnesia the dark descent), there they found a mysterious artifact in one of the huge halls, the castle was already quite destroyed and flimsy when they got there.

According to the lore of Amnesia, if you touch the sphere, you will be haunted by its Shadow, the guardian of the sphere, an organic mass, a kind of curse...

Hope was the first to touch the orb, and as soon as she did, the castle began to shake. Panicking, the two ponies grabbed the orb and put it in Hope's bag, then started running away from the castle.

However, as they ran, one of the bridges above the large hall began to collapse right behind them. Candlelight stumbled and began to slide off the collapsing edge of the bridge. Hope grabbed her with her hooves, and the orb slipped out of her bag and Candlelight slipped from Hopes' hooves.

Both the sphere and the pony fell onto the stone floor, the sphere shattered, and Candlelight hit her head on the stone, also breaking two of her legs from the impact.

Hope watched in horror, the castle quieted down, and there was dead silence.... Hope ran away, home...without telling anyone about what happened.

When Hope was running away, Candlelight was still alive, she saw out of the corner of her eye how Hope was running away, but because of her broken legs she could not get up and was left to die there, on the spot, next to the broken sphere.

By breaking the sphere, the ponies released the magic contained in it and it connected their souls with a silver thread.

Two months pass, during which Hope can't cope with her guilt and the pain of loss, she has nightmares, sometimes she dreams from the perspective of Candlelight... how she rises and walks around the castle after the event. She decides to return to the castle, for Candlelight, naively believing that she is still alive.

Candlelight is dead. But there's a catch... Hope sees her soul, but she doesn't see her corpse when she returns to the castle, and Hope thinks that Candlelight is alive. Candlelight also can't see her own corpse, and she thinks she's alive. This is because the sphere has connected their souls, and when Hope returns to their town (village, Ponyville, whatever you want to call it), she brings with her Candlelight's long-rotting corpse, covered in worms and maggots. Everyone who has the misfortune to witness this sight is horrified.