How it started: Twilight had been tinkering around with her magic and was looking through Star Swirl the Bearded's spells, when she found a particularly strange one that seemed to fascinate her. It was unfinished and the last bit was smudged- the whole spell seemed to be rushed- and Twilight wanted to test it out. When she did, she had messed up on an important part of the spell, bringing an incurable infection upon Ponyville, later spreading to all of Equestria. It even reached Princess Celestia, and Princess Luna. The first victim of the infection was Fluttershy. Twilight went into hiding, and Applejack, Rainbowdash, and Scootaloo took refuge in Sweet Apple Acres. Applejack is in a state of shock and is mourning Apple Bloom. Pinkie Pie is in an early stage of infection, while Rarity is trying her best to keep Sweetie Belle safe. Whatever Twilight is doing is unknown for now, her castle abandoned, and there being no trace of her anywhere.
I'll start making some art and I'll go more into detail on the story, I'll show some characters' conditions and stuff and if anypony else gets infected or if a cure is found later in the au. I'm actually so excited about this lol I'll probably make a project for each of the ponies- I plan on doing one of Celestia and Luna or Twilight first It's a wip but uh yeah it's something to work on :3