A/N: Episode tag to 1.11 Tarantella

He should have known better.

She might have been barely fourteen, but she knew her heritage well. Her parents had been prepared for all eventualities, and she had learnt the details of what she would eventually have to do for the last two years.

Le retour d'age might not have affected her yet, but they all – he included – knew better than to think it would be too long. Soon, it would be her in her mother's place.

And the Grimm had just let her go.

It had been nearly a year since she had lost her mother to the Grimm who hid behind a police badge, and Sally Marcinko just knew that she would become a true spinnetod soon. It was fitting that it was nearly Christmas – what better way to celebrate new life than to be born again?

And she would be born again, becoming the creature from the dark instead of ordinary Sally like she currently was. After all, a fully mature female spinnetod was the stuff of nightmares even full grown men – especially full grown men – shuddered to think of.

Nearly a year ago, when the Grimm had taken her mother, she had thought him an idiot for leaving her alive. After all, he knew as well as she did that it was only a matter of time before she replaced her mother.

She still thought the Grimm was idiot, but she couldn't bare him any ill will. As much as she hated the thought, by arresting her parents, the Grimm had done her a rather large favour, even though she doubted he had been aware of it.

She had learned everything her mother had to teach her, but there were still things she needed to know, things her mother had never known.

In taking her mother away, the Grimm had taught her how to be a better killer.

Unlike her mother, she would hunt those who would never be found, men from the drudges of society. All she needed was three every half a decade – she could manage that. And more than that, she would make sure she never made her mother's fatal mistake – she would never, ever, start to care for the man who would give up his life so that she could be her true self, instead of a withered crone.

Sally Marcinko would become a killer no one knew existed, coming and going before anyone knew even one person was dead.

In a way, even the season seemed to support her. Christmas and winter made people just a bit too careless, and hunting in the winter would be practically child's play, even for a fifteen year old who had never killed – or even seen a dead body – in her life before.

So yes, the Grimm should have known better, letting her go the way he did.

But as Sally smiled, and looked out at the crowd of prospective victims who didn't even know they were being watched, she found she was grateful.

This…was going to be fun.

A/N: So basically, this was a little self-serving, because I've always loved the thought of insane!serial killer!Sally ever since I watched that episode - we have a perfect set up for that, since spinnetods are basically built to kill, and it's not like she has her parents to serve as moral compasses once the compulsion hits her anymore...

Anyhow, I hope you guys liked this! As always, please don't forget to drop a review on your way out :)