Elsa wishes that her classmates knew how to form a line. Maybe if Slytherin had been paired with Ravenclaw it would be different, but somehow things have been arranged to put Gryffindor and Slytherin in the same Defense Against the Dark Arts class, and the new professor doesn't seem inclined to do anything about the mob of students huddled around the wardrobe.

"Who can tell me what a boggart is?"

A hand on the other side of the room shoots into the air, and Elsa shifts a little, taking a discreet step back. If there were a line, she would be standing at the back, hoping that the lesson ended before she got to the front.

You knew this was coming. And it's true, she did. She had stayed up late last night, first reading the chapter in preparation, then writing a list of what her greatest fear could be, and all the while praying that the new teacher wouldn't dare hold a practical lesson as the introductory class. So much for hope.

She reviews the list, and her fingers tingle uncomfortably. It's not hard, because there are only two items. 2) Everyone finds out; 1) Anna dead, white spreading from that terrible strand of hair, covering her small body in ice, and the knowledge that it's your fault, you could have stopped it –

"P-Professor Snape."

The poor boy looks so embarrassed, it's enough to lurch Elsa out of her thoughts. And the idea that someones worst fear could be Professor Snape… she gives Longbottom an encouraging look, although he isn't looking at her, and straightens her shoulders. Display confidence. No one will question you. No one will think twice. Her father's voice echoes in her head, and she wonders, distantly, how he knew so much. He was always in control, and she envies him.

"Everyone together now. Riddikulus!"

It'll be Anna, she decides. It always is, after all. Feeling a little better now that she knows what she'll be up against, she begins to make a plan. Laughing won't be easy, but maybe it'll be enough to make everyone else laugh for her.

Her classmates go up one by one, and every transformation elicits screams or gasps of horror or laughs of disbelief. She clenches her hands, reaching far back into her childhood, trying desperately to find a way to make a dead five-year-old funny. She's surprised to note that she's not the only one standing nearer the door than the boggart. The Potter boy is looking uncertainly towards the action, a guarded expression on his face. Elsa wonders with brief bewilderment what he could have to fear, with his fame and his protected childhood and his friends to stand beside him, but then she remembers why he's famous and hidden away. She wonders if he remembers that night, and decides he does.

If there is one thing worse than the corpse of a child, it is the monster that would kill them.

A sudden calming resolve creeps over her then, because suddenly she's not thinking of herself anymore, she's thinking of her classmates. She thinks that maybe they can handle the image of a too small girl, for all appearances merely asleep. She thinks that if there is one thing they can't – shouldn't – see, it is the nameless nightmare of a man whose very mention makes them quake in fear.

The crowd has thinned and Professor Lupin is speaking encouraging words, and between one transformation and the next, Elsa meets Potter's eyes, and steps in front of him. He looks at her with surprise and confusion, and suspicion. She doesn't feel anything but cold certainty that she has to be strong, and even though she hasn't laughed for years, she'll have to laugh today, loud and strong enough to break the boggart and drive it back into the wardrobe before Potter can do any damage.

"Arendelle, you're up, you remember the wand movements now, and the incantation…"

She's not even scared anymore, and it's such a relief she doesn't question it. She squares her shoulders and takes the final step forward, and the boggart is facing her and she's facing it, and it changes -

- it changes -

- it changes into her -

The implication of this is lost on the entirety of the Gryffindor and Slytherin third year class, including Elsa. The room is silent, but not scared silent, only confused.

"Professor, I - what?"

Murmurs break out behind her, and a snide voice carries over them.

"What does that mean? Is that you without make-up or something? Girls!"

"Hey!"

"Is that... scary?"

"P-Professor?"

"... she can be kind of intimidating..."

"You can't intimidate yourself, Lavender."

And the professor's voice, "... Elsa?"

The words fade, because she's finally figured it out. All this time her mirror image has been watching her almost as intently as she's been watching it. It's not a mirror image though, and Elsa realizes that it is the differences that serve as the final pieces to this puzzle. It fiddles with it's ungloved hands, intertwining it's fingers and twiddling it's thumbs, and a cool draft passes through the room, rustling it's hair... but that's not even the worst of it. Worst of all is it's face, and the expression of terror upon it.

"Fear will be your enemy, and death it's consequence." The words come to her like a half remembered dream and she doesn't remember when or where she heard them, but she knows in this moment that they are true.

She doesn't move, because she knows what will happen if she so much as breaths, and she wishes that she had never tried to be brave. Because the only thing worse than a dead girl is the monster that- that is standing right in front of her, and she is so afraid, and the last time she was this scared was that night in the living room when Anna had died.

"Elsa, breathe, you can do this. Ridikulus. Say it now..."

Professor Lupin's voice is alarmed, and at the same time strangely sympathetic. He's giving her a chance to face her fear, just like he's done for everyone else, but he doesn't understand what that fear can do. What the consequences will be.

Elsa can't speak, let alone laugh, and nothing about this is even remotely funny, so she does the only thing she can, and stumbles backwards, away. The others must be able to see how scared she is, because they're not laughing anymore, and confusion is slowly being replaced by the knowledge that something is wrong, even if they don't know what.

And then her double does what she cannot, and speaks. It's lips move soundlessly, but the word they form and its message is abundantly clear.

Monster.

Ice crackles along the seams of her gloves, and Elsa realizes suddenly what she should have known from the start. It's not the boggart that is dangerous, that is the monster. It's her, and she needs to leave before everyone else figures it out, before she can do any more damage, before she loses control, even though in a small corner of her mind she knows it's too late.

She turns, and runs, and doesn't look back.

I haven't quite decided what Anna's will be yet, but she's next. R&R :)