Buffy Summers was an ordinary earth pony foal until one day, she was visited by an old gelding who told her that her destiny was to fight the evil vampire ponies. "Vampires aren't real!" nickered Buffy. "That's just an old pony tale."
But that very night, Buffy was walking home from the orchard with a basket of apples on her back. She heard a noise behind her and was surprised to see a strange red unicorn pony sneaking up on her. "Would you like an apple?" she said politely.
"No," said the unicorn. "I think I'll have....YOU!" Suddenly his face changed. Buffy saw evil in his eyes and long fangs in his mouth.
"Those aren't for grazing!" she said. Before she knew what she was doing, she had attacked the unicorn and beat him into a bloody death with her bare hooves. It was okay though because then he exploded into wood shavings.
At that moment, Buffy's cutie mark finally appeared.
Much later, Buffy moved to town called Snaffledale. She wanted to put her vampire neighing days behind her, but her destiny was having none of it. Right away she met a handsome pegasus stallion in a dark paddock, and he told her that there were vampire ponies here too, led by the mysterious Foundation Sire and preparing for the prophesied Grazing.
"My name's Angel," said the pegasus before he flew away. "Let's just say...I'm a brony."
"How rude," thought Buffy. "He doesn't seem to know anything about the magic of friendship!" But the real truth of course was that she was head over hooves in love with him.
All was going fine until one night, when Buffy finally worked up the courage to nuzzle Angel. To her great shock and horror, his face changed and he growled at her - he was a vampire pony!
She decided she had to hunt him down and make him die a horrible death, as the Neigher must do to all vampire ponies. But when she found him again, she saw that he looked so sad and lonely that she couldn't do it.
Angel explained that he had devoured a thousand million ponies in his evil days, but then he was cursed with the Elements of Harmony, and now he only drank apple juice and brooded. He also said that he was completely in love with Buffy, but still kind of wanted to drink her blood, so they had better stay away from each other.
"But Angel," neighed Buffy. "Can't we just have a non-relationship tea party?"
"It's not safe," he said. "I can fly like a pegasus, but I'm not one. I wanted to nip you today."
And so they nuzzled for the last time, right in front of everypony. It was a beautiful, tragic, and unspeakably equine moment.
Edit: This seems to be more popular than I expected, so I felt I should add due credit - the pony pictures came from General Zoi's pony creator. I didn't draw them! All I did was add the cutie marks using images I found on Google.