Cotard

"Ugh...what's happening?", the fashionista mumbled as she groggily opened her eyes.

Rarity shook her head a bit and then took in her surroundings: she was in a dark, damp room. She scrunched her nose at the smell, all too familiar at this point. It appeared that she was on her back on a hard and cold surface. As she instinctively tried to move her limbs, she noticed that she could not budge them, and that was the moment when the unicorn started to panic as she thrashed to free herself.

"What is going on? Where am I?", she asked desperately, to no one in particular.

The mare continued to thrash in her bonds, but to no avail. She was starting to panic more and was on the verge of hyperventilating. In a fit of desperation, she decided to shout for help, but no one answered.

"C-calm down Rarity, maybe it's just a misunderstanding?", the mare tried to reason. She tried her best to look at her surroundings but couldn't assess anything in the dark.

The mare wished that somepony would came and free her from these bonds. In this day and age, she didn't even thought that somepony might hurt her instead of freeing her. It was probably just a misunderstanding. So she started to scream in the dark.

"Hellooo? Is anypony there? I am trapped in here, please help me!"

Rarity perked her ears in the hopes that somepony heard her. And she softly gasped in surprise when she heard a door creak open, followed by hoof steps.

"Oh thank Celestia! Please, untie me from these bonds, I have no idea how I got here!"

The unicorn was a bit surprised when the other pony didn't say anything or rushed to her side. In fact, the pony seemed to slowly trudge towards the other side of the room instead of the table she was currently strapped to. So she decided to wait in silence and see what they would do. She could even spot a flicker of green light from their horn.

The other pony seemed to fumble a bit with something from another table located in one corner of the room, then started to slowly trot towards the distressed mare.

"Please, can you help me?", tried Rarity again, only to be met with low, heavy breathing and soft grunts. Rarity had a hard time putting two and two together, but when the other pony came close enough, she screamed bloody murder. She thrashed fiercely in her bonds and began hyperventilating. She calmed herself, but only a bit, when the flickering, pale green light illuminated the undead pony.

"T-Twilight...? Darling, is that you?", Rarity couldn't mistake that navy blue mane and those two stripes of pink and purple, even if her mane now was frizzy and thin. Despite her rotting body, the resident seamstress could still notice patches of discolored purple fur on the other pony. And even though her eyes were now glazed and a sickening fluorescent green instead of violet, Rarity still recognized this abomination as her former friend and fellow Element bearer, Twilight Sparkle.

Rarity was so shocked that she didn't even notice when Twilight leaned in closer to have a better look at her. Although that appeared to be impossible, the undead pony seemed to study her closely.

The bound mare could only whimper as she looked curiously at her friend. Even though she was scared, Rarity was intrigued that her dead former friend had no intention, at least yet, to pounce on her.

When this all started, Rarity tried her best to survive. Not as much for herself as for her younger sister. And in all this time, the unicorn learned some things and patterns: this disease was magical in nature, the dead were always hungry and craved only meat, and that Twilight Sparkle was Patient Zero.

Rarity's mind replayed the vivid memory of an apprehensive Twilight Sparkle, that invited her for tea to "tell her something important". At first, Rarity was extremely happy when her friend told her that she believed Princess Celestia wants to transform her faithful student into an Alicorn. The white unicorn always believed that if somepony deserved to be an Alicorn, that was Twilight. But then, her smile faltered when Twilight told her that she messed up the spell she created in order to impress the Princess. Rarity was fearful, but would have no idea the impact Twilight's spell had until a few weeks later, when the mage started to feel sick and sometimes her eyes would flicker with a disturbing pale green. The white unicorn instantly had flashbacks from the time she was possessed by dark magic due to her own hubris. Considering she was the only pony that knew about Twilight's deed, the seamstress stayed with Twilight in the Golden Oaks Library. When the mess started, Rarity tried her best to protect her sister and Twilight. When it was obvious that among her friends, Twilight was the only one sick, Rarity, with a heavy heart, decided to send Sweetie Belle to live with Applejack and her family at Sweet Apple Acres. She knew her other friends were capable of taking care of themselves and it was all confirmed when she found out that all of them barricaded in their homes.

The memories became hazy after this point. What happened to Twilight? And how did she end up strapped to this table?

Her train of thought was interrupted when Twilight slowly levitated in her sickly green magic a square piece of rock and a broken shard of glass. The dead mare was mumbling like she tried to say something.

Her memory was blurry but she tried to remember. Something about her helping Twilight with some experiments, since the purple mare said that it might aid her in finding a cure, especially since she speculated that Rarity might be immune to the disease, due to her already encountering dark magic and overcoming it. Rarity was skeptical at first, but she had to hand it to Twilight: with her help, the infected mare managed to slow down the transformation, albeit no pony knew for how long. So the generous mare accepted, since she also hoped that Twilight will find a cure. Not to mention that she felt proud when she heard she might be immune and that she could help cure this deadly disease. The last thing she remembered was that Twilight said that it will be ok and that she can trust her, and she will administrate a weak anesthetic in order for the fashionista to not feel anything during the otherwise painful experiment.

"So then...", the mare thought as her eyes drifted back to the obviously deceased Twilight. Rarity tried desperately to piece two and two together, and her blood ran cold when she reached the frightening conclusion.

"So she sedated me with a strong anesthetic and during this time, she succumbed to the infection. But, Twilight does not make this sort of mistakes. So did she sedate me intentionally, knowing what was to come, or in her addled state, she truly made a mistake?", Rarity did not have more time to think as the shard of glass hold by Twilight's magic came down messily on her shoulder.

The unicorn shrieked, thrashed wildly and begged the undead pony to stop. Twilight seemed to acknowledge her, but only for a second. She mumbled something again while still holding the rock, and she plunged the shard again in Rarity's belly.

The mare sobbed bitterly, salty tears streaming down her face. She stopped thinking, stopped begging, stopped shrieking. All she could say was:

"W-why...Why is this happening to me?"