Twilight Sparkle was walking home at night from Sugarcube Corner. She was helping Pinkie with some orders for customers. She had stopped by Rarity's house to get Spike a ruby for a snack.
"He's going to love this!" said Twilight.
"Love what, Twi?" Twilight turned around to see Applejack standing there.
"Oh, hey Applejack. You scared me. I got Spike a ruby. I never understood why dragons like gems as food."
The two ponies talked a while and Applejack ended up walking with Twilight, because Sweet Apple Acres was on the way. As the two walked on Twilight began hearing a dripping noise.
"You hear that, AJ?"
"Yeah...that water," said Applejack. "Probably from a well somewhere, I reckon."
They were wrong.
Twilight eventually found the cause of the dripping. A stallion was walking under a street lamp. He had a red mane and a full white body. Blood was seen dripping from his face.
"Somepony's been in an accident!" said Twilight.
"My gosh- I'll get some help!" said AJ. She ran to city hall, the closest building near here.
"Sir, are you-" was all Twilight got out before the pony lashed out at Twilight's neck.
The pony was no ordinary pony. His eyes were gouged out and his teeth were razor sharp. He continued biting down on Twilight.
When Applejack returned, The strange pony had left a trail of blood leading to the Everfree Forest. He was never found. All that WAS found was the body of Twilight Sparkle. A large chunk of flesh was missing from her neck. Everypony was left devastated without her. Spike became Rarity's assistant.
The odd pony- no, monster- became known as "The One With The Blank Flank" because Applejack recalled seeing no cutie mark.
This beast was the word around town for some time, until after Twilight's funeral. But of course, that's when it paid a visit to Sweet Apple Acres...
Credited to Bladesofwoe