"Transfiguration is as much an art as it is magic."
"The ability to transfigure things from their basic components into something else at the price of using up some of your spirituality to hold the change is called transfiguration."
Diagrams popped up on the blackboard behind McGonagall as she continued to explain the process of Transfiguration.
"There is only one way to achieve transfiguration, and that depends on a fundamental equation, aZ^2 + vC^2 = w, where 'a' is the mass of the object, 'v' is the viscousness, 'Z' is the rate your spirituality accumulates, 'C' represents your concentration where 'one' indicates full concentration and 'zero' is none, and 'w' is wand power".
"Ideally the variable, your concentration, must be at its peak to produce the most perfect transformation, while the rate at which your spirituality accumulates must be one magical moment."
"The equation when plotted with their respective values and using one as the value for everything else gives us a horizontal semi-circle since your concentration cannot be negative."
A semi-circle-like cap appeared on the blackboard magically and once it was done, McGonagall turned towards everyone and asked a simple question.
"Does anyone know the wand movement to undo a transfiguration?"
Hermione's hand shot through the air, but this time even Loki raised his hand up with a little confusion.
But McGonagall chose Hermione to answer because she raised her hand first.
"The wand movement to undo a transfiguration is a half semicircle in the form of the letter 'u' professor."
"Five points to Gryffindor because you are right Miss Granger.", McGonagall said with a smile, but Loki's hand was still in the air so she with raised eyebrows asked Loki to speak.
"What is it Mr. Loki? Gryffindor has already gained the points, I'm not going to give you points even if you know the answer."
"Ah! No, I wasn't worried about points, but I have a doubt."
"And what will that be?"
"I wanted to know if there is any relation of these half circles to the meanings attached to the half circles in Arithmancy?"
"You've read up on Arithmancy Mr. Loki?"
"Only a little bit Professor."
"Since the question is beyond the scope of this class I will not answer it right now, but why don't we take this up today during our detention."
"Alright." Loki nodded and sat back down while McGonagall continued the lesson.
Soon it was time to put everything they learnt into practice and so McGonagall levitated matchsticks to each student sitting in the room.
"Your task is to transfigure this matchstick into a needle! The relevant information about the constants involved are on the board, you may begin."
With McGonagall's permission, everyone began to make a half circle like a cap with their wands while expelling spirituality with calculated precision and imagining the outcome.
It took a while but by the end of class, Loki's matchstick slowly gained a silver sheen and became pointy on one end causing McGonagall who was walking around class to award him Five points.
This seemed to have fired up Hermione because immediately after she transfigured her match into a needle look alike and gained five points for her house too.
But Loki noticed something strange during the class, 'Why is it easier to transfigure now than at the beginning? I'm sure my concentration hasn't improved in such a short interval, so why is it easier?'
"That will be all for today! Undo the transfigurations on your matches by doing a half circle and saying the word, 'Reprifarge'." McGonagall interrupted Loki's thoughts by reminding everyone of the end of class.
A stream of Reprifarge was heard all throughout the room and everyone's needles became normal matches once again which McGonagall collected.
With the end of the Transfiguration class, there were no new classes to attend and Loki went back to the black lake to practice manipulating his spirituality outside his body by making geometric patterns on paper.
He did till it was seven when he had dinner and left to go to McGonagall's office after asking Dominic for its location.
"You have detention with Professor McGonagall?" Dominic asked surprised.
"Huh? Is there something I should know?"
"Well, it's just that Professor McGonagall usually never takes detentions. At least I've never seen her do so."
"Huh? Well, maybe I'm just special like that."
"Surely you jest."
"You're just jealous."
"Haha~ Sure, sure~"
Arriving outside McGonagall's office Loki knocked on the door twice in sharp intervals and waited patiently for a voice from inside to give him permission to enter.
"Come in." An aged voice that still held its edge sounded from inside as Loki entered the room by peaking in a little at first and after he saw McGonagall looking at him amusedly he entered fully.
"Professor!" Loki said with a soft bow.
"You're here early. I thought Professor Snape wanted you first."
"He did?" Loki asked confused.
"Oh don't tell me you didn't inform him that you were coming here?"
"Well, I might've forgotten.", Loki said with slightly red ears.
"*Sigh* Don't worry, I will let him know."
McGonagall quickly penned a note and swung her wand for an ethereal white mist to pour out of it which transformed into a tabby cat that was looking at her expectantly.
Handing the letter over to the cat, McGonagall nodded and the cat slipped out from under the door.
"What was that? A spirit or something?" Loki mumbled.
"No it was a way to summon your contracted spirit called the Patronus spell, don't worry about it. It is an advanced charm that uses happy emotions to call upon your contracted spirit to defend you from a few dark creatures."
"Dark creatures? Like Boggarts?"
"Haha~ No, not boggarts, I meant Dementors. Though they're both amortal, of the unkillable sort."
"Oh! My wand is made out of the bone of a Dementor!" Loki said showing off his wand that was a pointy white bone.
"Is it?" McGonagall asked a little shocked.
"Yes, well that is what Mr. Ollivander said when Professor Snape took me to get a wand."
"I see. I did not know about that, did Ollivander give you any warnings while using the wand?"
"No he didn't, all I learnt was that the wand was made with unicorn hair as the core and the bone of a dementor as the body."
"That is a strange combination Mr. Loki."
"I know."
'I really should study up on Dementors and Unicorns, it is probably bad if other people know more about my wand than me.'
"Well this is just a time as any to start our detention Mr. Loki."
"Oh! Sure! What are we learning about first? The question I had in class about Arithmancy? Or something else?"
McGonagall smirked and said, "We will learn about those, but only at the end of your detention, for now, I am a little busy because I've been swamped by work due to the new year, so you will help me grade a few summer homework submissions from the students."
"Arghhh…not you too! Professor Flitwick already made me do this and it was boring!"
"Don't you want to know the answer to your question Mr. Loki?"
Seeing Loki not respond but look at her with a soft accusing glare McGonagall laughed and said, "Then I suggest you to get to work quick!"
"Fine." Loki nodded and began helping McGonagall grade papers.
After nearly a couple of hours, when McGonagall deemed that all the papers were graded perfectly she spoke up. "Thank you Mr. Loki. You've been very helpful."
"Oh please, all I've done is add a few numbers and written up the result. You should get a calculator for this, it'll help you better."
"I've heard about it, but unfortunately Hogwart's spirituality interferes with the workings of electronic devices."
"Hogwart's spirituality? The castle is alive?" Loki asked a little shocked.
McGonagall's eyes widened as if she only just realised the slip of her tongue but she relaxed and said in a kind tone, "Well it isn't a secret since you'd learn about it if you browsed through the library for books on Hogwarts herself, but yes, the castle is alive, at least it seems to be since no one has ever been able to speak to her."
"I see!" Loki said with sparkling eyes.
"Haha~ I wish I could share your enthusiasm but I've already given up on speaking with Hogwarts herself, perhaps one of you students, maybe even you might speak to her. Now off you go, trot back to the dungeon you crawled out of."
"You've still not answered the question I asked in class today Professor!"
"Oh yes, yes, your question. The answer is yes, the half circles do have a relation to Arithmancy. Every transfiguration is only complete when it is untransfigured."
"What do you mean?"
"The two half circles that are used in Transfiguration are two halves of one whole, meaning that transfiguring causes our spirituality to be used up. This used up spirituality becomes the source of energy that holds the changes in the object and prevents it from reverting. It makes it tense like a stretched elastic band."
Seeing Loki was following her so far, McGonagall continued.
"But undoing the transfiguration releases the spirituality and sets the object into its original state, like the release of a spring."
"Is not reverting it to its original form wrong?" Loki asked confused.
"Not exactly wrong, but- here- wait a second and cooperate with me." McGonagall said, pulling out her wand and tapping Loki's hand.
In a swirl of colours, Loki immediately transformed into a white cat that was sitting on the chair.
"MEOOWW!!!!!!" the cat screamed.
"Haha, yes, I know it is strange but hold on! Can you see how you feel?"
"Isn't it strange and uncomfortable?" McGonagall asked and the cat looked at itself and then calmed down a bit.
Once done analyzing his new body, Loki nodded, 'It does feel strange. Like I've been stuffed with cotton. Or like I'm a balloon that's been stuffed with air to the brim. Any more and I'll explode.'
Once Loki nodded McGonagall tapped his head with her wand once again and caused him to reappear seated on his chair.
"That was uncomfortable Professor.", Loki complained but McGonagall didn't mind as she continued to teach.
"And that is exactly the point, transfiguring an object into something else makes its structure tense. Leaving it in such tension for a prolonged period of time will make it weak and fragile. So it is not advised to transfigure things for a long time or even repeatedly."
"Oh so that's why-"
"Yes, that is precisely why you found it easier to transform the needle towards the end of the class because your repeated attempts at transfiguring it weakened its structure."
"I see." Loki nodded in understanding. "Thank you professor."
"No problem, off you go now."
As Loki walked back to the dungeons he had a single thought on his mind, 'Professor McGonagall's so sweet outside class.'