On the Pretty Little Liars TV show, there is a scary story about two twin girls. It is told by Alison when she is babysitting. The story appeared in the special Halloween episode The First Secret.
This is how I heard the story:
The twins played so nicely while they waited for their parents to get home. But they wouldn’t get to go trick or treat that night… or ever again.
She lifted the knife high into the air and then plunged it deep into her sister’s chest.
A sick smile came across her face as she watched the blood ooze out of her sister’s heart
And they had no choice but to send her away to a home for the criminally insane.
And that’s where she remained until yesterday when she escaped and vowed to return to Rosewood and stab to death every child who dares to go trick-or-treating on Halloween…