That one episode where Applejack goes AWOL and the Mane Six... er Five go to find her and Pinkie Pie jumps off of a carriage saying "Catch me Rarity" and Rarity was caught off guard so they both fell off of the carriage. They had to walk back to Ponyville in this comic. In the original episode they had a trolley.
Then the vulture suddenly slashes Rarity, much to the shock of Pinkie, and when the pink pony tries to kill the vulture, she gets her throat cut and slowly bleeds to death as the vulture noms her friend.
And both of them haunted Rainbow Dash, who becomes overly stressed she kills herself, becoming a ghost, joining Rarity and Pinkie in haunting Applejack in return (because they blame her), only to find the CMC in their "Ghost Buster" cutie mark crusading catching them in a heavily modified toaster.