The Monkey's Paw

Granted. You're not sure whose little sister she is, but she's 5 years old, crying, and there are sirens outside.

Granted.

In the near future, while going through your own birth records, in a file you had overlooked before, you notice there's another certificate of live birth, hours after your own. Your own last name. No first name, just a gender: female. And no other papers or information. It must have gotten mixed in with your own records by mistake, and then sat undiscovered for decades.

You call your parents to ask about it. Your mother bursts into uncontrollable tears. She's can't talk, like, at all. Your father, slowly, explains what happened. What he tells you is hard to accept.

Legally, he's your father. But your mother had had an affair the year before you were born. He slowly explains that mistakes were made on all sides, that he loves you and your mother very much, but that you are not, biologically, his child.

And, yes. You had a twin sister. It was a difficult birth, and was unexpected. They had no name picked out for her.

But your biological father? The one with whom your mother had the affair? He was angry she'd broken things off with him. Very angry. He'd learned about the pregnancy, knew she was at the hospital to give birth. He'd broken into the hospital and reached the delivery room soon after your sister was born - there wasn't any real security back then, and he'd told the staff he was a "family friend."

You were safely in another room when he burst in, pushed the doctors to the floor, and broke your newborn sister's neck.

The trial was short. There were many witnesses, after all. Your biological father was convinced of infanticide, a horrendous crime for which he was unrepentant. He was executed the following year

Granted. You receive one copy of the original BioShock on CD-ROM. It's unplayable due to Windows Live shutting down.

Granted. Conjoined twins or dissociative identity.