"The Thin Ice!" Thalia dramatically announced, revealing a small mirror that had been hidden behind a thick velvet cape. Placed on an old wooden easel, it was about a feet large, and it was perfectly square. In the sunlight, the piece of what seemed to be glass reflected the class sitting before it, it's smooth and polished surface acting just like a regular mirror. If Hermione hadn't seemed impressed, Harry would have thought that was what Thalia was presenting them. Only, after a while, the image faded, then completely disappeared, leaving the piece of what seemed to be glass was as clear as crystal, and Harry understood why it was called Thin Ice: he could see through the mirror as if it had been nonexistent. He could easily distinguish Thalia and her belongings through the object, without any distortion. "It's even clearer than glass," Harry thought as he looked at one of the class windows in order to compare it's purity with the Thin Ice. Harry sighed. Today, any piece of junk would seem like crystal compared to the dirty, frosty windows of the castle. It was a gloomy December day, and though it was only a week before Christmas vacations, it seemed like happiness was years away. For more than a week, the dark sky had been spitting a cold drizzle all over the castle grounds, and now the small drops of water had frozen into a thick coat of ice that prevented the students from stepping outside without slipping and cracking their heads open. Also, as usual, the teachers had literally doubled the amount of work, in order to to compensate for the upcoming holiday. Therefore, when Thalia had announced that she had reserved a special object for them that day, Harry and Ron had imagined themselves meeting with something… a little more challenging than a piece of glass that was so thin it seemed that it could be broken with a simple wink. Harry looked at Ron, who replied with the same disappointment look. Only, they both glimpsed at Hermione, sitting a few desks further, who looked simply ecstatic. When their eyes met again, they were filled with anticipation. Harry whispered to his friend: "What do you think it is?"
"I don't have a clue," replied the redhead, "but it's going to be good."
"Now Remus – Professor Lupin told me," started Thalia, quickly realizing that almost nobody knew their former teacher's real name, "that you had already met a Boggart." A wave of approval crossed the class, as everyone nodded affirmatively. "Good," the teacher continued. "So can anyone here tell me what a Boggart does? Yes, Seamus?"
"It shows you what you fear the most," said the boy who had never before answered a teacher's question.
Harry smiled as he saw Seamus blush at Thalia's recognition. Their new teacher seemed to have the same effect on boys as Gilderoy Lockart had on girls about three years ago. "Hope she's not as stupid," he muttered to himself.
"And if I tell you," Thalia went on, unaware of Harry's comment, "that the Thin Ice almost has the same properties as a Boggart, can anyone of you guess what this here does?"
Hermione lifted her hand within a quarter of a second. Harry could see she had been preparing herself for this moment. Thalia looked at her and giggled. "Someone who doesn't already know the answer?" Miss Beauregard added. "No, none? Well then darling," she said to the owner of the hand that was frantically being waved in the airs, "it's your time to shine."
"The Thin Ice doesn't show you what you are scared of, it shows you what you should be scared of. In other words, it shows you the most imminent danger that is threatening you."
"Almost perfect," Thalia said, to Hermione's great displeasure. "You are absolutely right about the true effects of this mirror, but you have one little thing wrong. It's…" Thalia started, unsure of what to say. "I'll try explaining it with an example, so you can understand better. First of all it's important to say that this glass, though it can see in the future, cannot show you the future. For instance, if the greatest peril to my life is a car that will run over me in a few years or so, the Thin Ice will not show me myself being ran over by a car, but the car at this instant."
"And if the car doesn't exist yet?" a student asked.
"Then the mirror can show me the driver of the car, or the manufacturer of the car, or even the very pile of steel that will one day be transformed into a car. Or," Thalia added, as the class giggled, "if the person that is to run over me is going to be drunk that day, the mirror might show me a flask of Fire Whiskey, or even water that will later on be mixed to other ingredients to make that ounce of Fire Whiskey."
"Then how can you know what's going to happen to you?" Ron asked, puzzled. "I mean, if I saw water in the Thin Ice, I would think that I would die drowning or something like that, not ran over by a drunk driver."
"The reading of the Thin Ice is very complicated to learn and is usually taught to wizards who decide to specialize themselves in Divination."
Hermione's suddenly took a horrified look. Divination, which was an inexact science, had lost her respect years ago, and she usually preferred avoiding anything that resembled in any way to this "useless rubbish", to quote her. "But don't be scared," she added at the sight of Hermione's expression, "I won't try to show you how to understand these messages today. First of all, because it is nearly impossible to read someone else's Thin Ice for them. This artifact usually shows us events or objects that are linked to our past: therefore if you ignore someone's past, you can't know their future. Also, these objects base their predictions on symbolism, which is also quite hard to master. It took me more than a year to learn how to interpret these messages for my own, and I thank the Lord every day that I had such a comprehensive teacher to guide me into the deep abysses of Occlumency and interpretation."
"Well of course your teacher stayed with you," Harry heard Ron whisper to his intention, "you sleep with him!"
"What was that, Mr. Weasley?"
"Errm… Then why are you showing us the Thin Ice?" he quickly improvised.
"For many reasons," Thalia replied, apparently satisfied with Ron's answer. "First of all, this subject won't be in any exam, and I thought that you would appreciate a little time off taking notes."
The entire class sighed in relief, as if one, and quickly enough the sound of quills and parchment being put away echoed between the room's stone walls. Even Hermione quickly threw the already filled up piece of parchment she was using to take notes into her bag. "It's probably just to boycott any form of Divination," Harry explained to Ron. After a few seconds, the class fell silent again, awaiting to learn more about the now fascinating object that lied before their curious eyes. "Alright, now that you have all proved to me that all students follow the law of the minimum effort, here are another few reasons for presenting you the Thin Ice. Usually the class in which I show the Thin Ice is rather fun, even if you need to take notes, and most people find this interesting. Also, I recently learned how to craft these, and therefore I have about a dozen of them just lying around in my office for no purpose. Plus, these objects are very useful in one's life, especially around the times Voldemort decides he's going to treat himself to a little fun, like now." The class remained trapped in an uncomfortable silence, until Thalia spoke again. "Now to show you the last property of this artifact, I will ask you a question. What do you think I would see if I looked at myself in this mirror? No no, don't answer out loud. Simply think about it."
Harry did as he was told, and he rummaged through his brain at the research of someone that could possible mean harm to Thalia. In total, it took him about a second to get a list of twenty names. "Of course, Voldemort would want to kill her, because she left the Death Eaters and the punishment for that is death. Also, all the other Death Eaters would want to kill her, since she is fighting against them now," Harry pointed out to himself. "Plus, I'm sure Sirius could very possibly kill her…" After a while, he set his mind on Voldemort, already knowing he would be wrong. After all, how was he expected to know Thalia's enemies? He wasn't the only one who thought so. After a while, the students were starting to give each other concerned looks, and a brave Slytherin student even dared to comment. "But how are we supposed to know how you are going to die?"
"It doesn't matter at all if you're right or no… You don't even need to be close…" she explained. "I just want to demonstrate something without forcing you to think of your own death. So, everyone ready? Lets discover what I should be scared of…"
Saying so, she placed herself in front of the mirror, and gently blew on it, as if she was silently whistling. When she stepped back, the entire class could see, reflected on the mirror a big, gray rat. Every student frowned. Apparently, whatever they had in mind was far from what they were observing. Thalia laughed. "Is this not what you expected to see?" she asked.
"You mean… this rat is what you should worry about for your life?" Hermione replied.
"Who said it was for my life? This Thin Ice shows me what I should be scared of in this present time, which is this rat. Believe it or not," she explained, "it has been nibbling all of my clothing for the last few days."
"So does this mean you're never going to die?" Ron added.
"Why should you think so?"
"Well," the student said, "if the thing you should be most scared of is wrecked clothing, I would believe that you have a happy and eternal life ahead of you."
Thalia simply smiled, of a sad smile that left Harry puzzled. Then, without adding a word, she walked to the back of the class and exited, using a small wooden door that was simply cut out in the wall like any other that, but that somehow had managed to stay unnoticed to Harry for now four years and a half. Before the students had even time to start talking to each other, Thalia stepped back in, holding two square, book-like objects wrapped in the same purple velvet material that had covered the Thin Ice. She gently deposited them on her desk, and she unfolded the thick envelope surrounding the mysterious package. When she was done, Harry saw she had brought with her two other Thin Ices. She took the one on top and she placed it on an empty easel, identical to the one holding the first item. "Now you see, not all Thin Ices can see as far in the future," she finally mentioned. "The thinner a Thin Ice is, the more accurate it is, and the furthest it can see. The one I just showed you, I made myself, and therefore it is quite thick. It can only show me what I should fear for the next 24 hours or so. This one, on the other hand, was made by an expert in potions, and it is therefore much thinner. I can't remember exactly, but I think it's time range is of about a week." Harry couldn't believe it, but it was true: the piece of glass was even thinner than the original one. He couldn't believe that the original could even be considered thick. It was so small and slender, and it didn't seem any larger than a muggle mouse pad, which was quite slim for glass. The second one, on the other hand, was as slender as building paper. "Just to make it clear, I'll try giving you common examples. If, Mr. Weasley, lets say," Thalia said, smiling at Ron, "used the first mirror, he would probably see the image of his two twin brothers, as they are the cause of the most… unpleasant event that will happen to him tonight." Replying at Ron's inquisitive frown, she added: "I would double check my bed tonight if I were you." Abandoning the more familiar tone of voice she had been using, she returned to her explanation. "Then, if Mr. Weasley consulted this mirror," she said, approaching the mirror she had just brought into class, "he would probably see his beloved Defense Against the Dark Arts teacher, or the roll of parchment which will be used to write the hour-long exam he and all of his little comrades will receive right before the Christmas vacations."
All the students complained, but Harry had to admit that Ms. Beauregard had been kind enough of warning them in advance. "If he then moved on to an even thinner Ice, he would then be showed the biggest threat lying upon him for the next month."
"Could he see the biggest threat lying upon him for his entire life?" Malefoy asked, talking to Ms. Beauregard for the first time since the Devil's Fog incident.
"Yes he could… But the Ice if too thin for me to bring it in class."
She seemed to be choosing her words, weighing each and every one before daring to pronounce them. "Could we go see it in your office then?" Malefoy continued, curiosity shinning in his pale eyes.
"Absolutely not. A wizard that discovers the cause of his death is bound to go mad. He lives in constant fear, and his death becomes his only obsession. He ruins his whole life trying to save it."
Thalia fell silent, and the students imitated her. Her discourse resembled to what Dumbledore had told Harry when he had discovered the mirror of Erised. "Wizards," Harry thought, "really do have a knack for inventing mind twisting mirrors."
"Anyways, the advantage with thick mirrors are that the images they send are easy to understand, even for students. Therefore," she said, placing the third Thin Ice on it's respective easel, "I brought this one. It was my first success, and is only capable of predicting the next two or three hours, but I thought you could have fun with it for the rest of the period. All you have to do is stand still in front of it and gently blow on it."
She didn't even have time to finish her sentence that a horde of eager students threw themselves to the front of the class, creating a messy line on front of the fragile artefact. As they Slytherins and Gryffondors had fun predicting their future, Ms. Beauregard started putting away the other two mirrors. Only, Harry noticed that as she gently blew on the second Thin Ice, her eyebrows formed a deep frown.