I've been writing like mad lately, here's yet another of my random works.

I own nothing.

Minerva McGonnagal sat peacefully at her desk in the Deputy Headmistress' office, marking papers from the third years' Transfiguration assessments.
Pass
Pass
Fail
Pass
Fail
Pass
Pass
She enjoyed this part of teaching almost as much as she loved giving Slytherin students detention.

Speaking of Slytherin students, that was the moment that the sixth year Slytherin, Bellatrix Black, entered her office, brandishing a piece of parchment.

Minerva took the parchment without saying a word and pursing her lips, she began to read:
Minerva,
I am very sorry to give you extra work to do as I know you have a lot on your plate at the moment. However, Miss Bellatrix Black of Slytherin house has been up to no good... again. I feel that my tactics are not getting through to her and that perhaps you would know how to disciplin her. And also, please don't send her back to me, she almost poisoned my brandy and I'm a little scared of her.
My deepest gratitude!
~Horace Slughorn~

Minerva sighed heavily and without moving her head, she glanced up at Bellatrix who was perched on the end of her desk and appeared to be trying to use her wand to set a quill on fire.

"Miss Black," said the Professor coldly, "Take a seat."
Bellatrix giggled and crossed her legs, proceeding to lean back on the desk, "But Professor, I'm sitting already! Do you think it's time you got stronger glasses?"

Eyes piercing cold, Minerva spoke again, firmer, "On the chair, Miss Black."
Sighing dramatically, Bellatrix hopped off the desk and, twirling a dark strand of hair around her finger, she plopped into the chair opposite her Deputy Headmistress.

Minerva put the papers to one side and adjusted her glasses before leaning forward slightly and speaking calmly, "Now, Professor Slughorn has informed me that you have been up to no good again. Care to elaborate on that, Miss Black?"

Bellatrix grinned as if this were all a joke and leant back in her chair casually, taking full advantage of slouching around whilst her mother wasn't there to tell her off. Beginning to laugh, she explained, "Well you see Professor McGonnagal, myself and the Lestrange brothers, Rodolphus and Rabastan, were innocently on our way to the Great Hall for breakfast when a little first year Hufflepuff had the nerve to run straight into me!" she acted offended, "So naturally, Rodolphus shoved the Hufflepuff out the way but I wasn't finished with him, you see! I grabbed the little brute by the collar and used a couple of spells on him. Nothing major, you understand," she shrugged and smiled smugly, as if impressed by her own actions.

Minerva inhaled deeply and raised an eyebrow.
"Which spells, exactly, did you use?"

Bellatrix began chewing on the ends of her hair and smirked, "Incendio mostly. We'd been learning it in Charms so, as I'm sure it's apparent, I was merely practicing for class. Shouldn't I be getting extra credit?"

Incendio. Minerva shook her head disapprovingly. She had set a first year on fire. And what was worse was she seemed proud of it! How like the rest of her twisted family... Why couldn't they all have been like Sirius or Andromeda Black? Actually, no, Sirius was as bad a troublemaker as his Slytherin relatives. Why couldn't they all have been like Andromeda? Slytherin, yes, but good hearted.

Professor McGonnagal removed her glasses and massaged her temples.
"Which brings us to the next thing, Miss Black; tell me that Professor Slughorn was joking when he explained that you tried poisoning him!" she said, the calmness wearing off quickly.

Bellatrix rolled her eyes as she started to play with the buttons on her school robes.
"It wasn't poison, Professor, it was a memory potion!"

"And why on earth were you trying to slip your Head of House a memory potion?" she asked, raising her voice and frowing.

"Only to make him forget what he'd seen me and Rodolphus doing in the broom cupboard!" Bellatrix's eyes widened as she realised what she'd just said and her cheeks turned crimson.

The cheeks of the Deputy Headmistress turned a colour to match; her's in fury rather than embarrassment, "You did WHAT?"
Bellatrix sunk down in her chair, trying to hide laughter.

"Detention until Christmas! Every Monday, Wednesday and Friday! In my office, five till nine!" she yelled, "Now get out!"

The dark haired Slytherin huffed as she stood up to leave, finding her punishment extremely unfair. She took out a cigarette from her robes and lit it with a flick of her wand before she left, waving goodbye to the professor as she swept out.

Minerva, infuriated, took a deep breath and tore up Slughorn's note. Bloody Blacks... Bloody Slytherins... She made a mental note to herself never to become involved with Slytherin house again.