Preston thought a moment, considering his students questions and wondering how best to address them. He tried to push aside concern over the two who were apparently hypothesizing how one might eat and/or kill a cat, though he stroked Princess a little nervously.

"Always ask questions. Though, perhaps the more unsavory should be saved for after class." He looked pointedly at Miss Flores and Mr Danford, before turning his gaze toward the young Slytherin who looked ill. "If you need the healer, you may be excused," he added gently.

Placing Princess down - but keeping an eye on her box nearly at all times - Preston pursed his lips.

"I fear we may be treading over the heads of some of our younger students. This is very abstract, advanced discussion, and I commend those of you who have kept up."

Preston folded his arms across his chest and considered another moment. "I think we are having a problem of language. The same word can mean different things. Being, nature, appearance. All imprecise. Let me try to be plainer." He looked to the students who had asked questions before addressing the entire class.

"When I say appearance, I do mean that which is observable. Change a mouse into a teacup and it will, for all intents and purpose, be a tea cup to all who observe it, who interact with it, who use it to drink. It also will not think or have desire or get hungry. But, at the same time, there is a... tether, let's say, that connects that teacup to its previous existence as a mouse. The mouse continues to live, even though the teacup shows no signs of life. When it is no longer a teacup, it will be the mouse it was before, and not just any mouse. The essence of mouse, you might say, remains."

"To go back to the example of turning Prefect Laksh into a cat, yes, she is correct that she would no longer even think like herself. She would have the instincts, desires and intellect of a cat. She would look like a cat, inside and out. But who she is doesn't disappear."

Preston paused and nodded in the direction of Miss Stone. "As an aside, yes, you are correct that animagus transformations are different in that the person retains their intellect and simply takes the form of an animal."

Pausing, Preston turned to the blackboard, erasing the instructions from earlier and simply writing "Gamp's Laws" across the top.

"Sometimes its helpful to know what can't be done, in order to understand what can. Earlier, one of your classmates mentioned Gamp's Laws. Who can tell me what that refers to and what they are?"

ooc: One answer each, please, to spread it around. The entirety of Gamp's Laws are not in the HP canon, though several suggested lists have been made. I have a list that we'll be using, but for this part, feel free to be creative around what sorts of transfiguration isn't possible. We don't bite. Promise.