What material is this?

"How did you get here?" Anthony asked.

Tracey mumbled, "I'm sorry, I was distracted, Professor." She turned and started down the stairs. "I think I've been a bit sleep-deprived lately."

Anthony nodded calmly and followed. "Alright, Davis, I hope you get a good night's rest."

The dungeons were colder than other parts of the castle, and the torches burned dimly, casting long shadows along the corridor. Their footsteps echoed eerily off the stone walls.

Anthony escorted Tracey to the entrance of the Slytherin common room, watched her give the password, then immediately returned to the abandoned bathroom.

If the Weasley twins hadn't shown him their former "secret base" when they handed over the Kneazle egg, Anthony wouldn't have known how to enter the room with its rusty lock. He found a piece of wire under the door – he secretly doubted Tracey had actually used the twins' method to open it – and laboriously fiddled with the lock, mimicking George's demonstration.

The door creaked open. Anthony stepped inside.

The interior was different from his last visit. The air was thick with the scent of potions. A cleaned crucible sat beside the sink, potion ingredients were neatly arranged on the toilet the twins had converted into a shelf by the entrance. The entire room had been tidied up, except for the ceiling. The toilet seat, sporting a colorful wig and a wide grin, still retained the Weasley brothers' unique touch.

The toilet seat had been chattering away since he entered. "Welcome, honored guest! Welcome to the lovely lavatory! May you have a lovely day as a toilet! If not, may you have a lovely tomorrow as a toilet."

Anthony shoved it into a nearby unused stall. The toilet seat hummed with satisfaction and fell silent.

...

Anthony frowned at the rows of potion ingredients before him.

Corked bottles held stones with an unusual sheen, crystal vials contained viscous liquids, neatly compartmentalized boxes held scales of various sizes, and dried herbs were stored in breathable linen pouches. A strange odor emanated from one bag, jars held powders of different textures and colors, and there were even... well, dead insects preserved in light-shielded, dark brown glass bottles.

As Anthony and Neville had once observed, he knew nothing about potions. Expecting him to deduce Miss Davis' activities from this assortment of ingredients was as likely as Moaning Myrtle popping out of the toilet to explain the situation.

Fortunately, the castle housed a certain individual rumored to be a potion master. Albeit one who, as of yet, had not received the esteemed Order of Merlin, Second Class award. And Tracey happened to be a student in his house.

...

He knocked on the dark door, and it opened immediately. Snape glared at him. "I hope you have a good reason for this, Anthony."

"I believe I do," Anthony replied. "Probably."

"Very well, enlighten me," Snape said impatiently. His voice echoed in the corridor, making the dungeon feel even colder and quieter.

Anthony apologized slightly. "It might take a bit of your time... I need your assistance identifying some potion ingredients."

Snape retorted, "Unfortunately, not every professor has the luxury of doing nothing all day, sipping tea, and strolling around chatting." He stepped aside, revealing a bubbling cauldron behind him. "As you can see, I'm rather busy. It's not part of my job description to indulge my colleagues' ignorant curiosity, especially when I have brewing to attend to."

Anthony smiled. "But this isn't just about my curiosity, it concerns a student." Seeing Snape about to refuse again, he added, "I believe I mentioned last time, you can't simply ignore students. And the good news is, I have an excellent memory."

...

"A handful of long, slender, spiny solids with a black tip, about this long. Contained in a glass bottle."

"Porcupine quills," Snape replied, frowning.

He stirred the contents of his cauldron three times clockwise, lowered the flame, then turned back to Anthony with a menacing look. "It's been half an hour. What exactly are you after, Anthony? A quiz on basic potion ingredients?"

"Not quite," Anthony said, pausing to consider his words carefully. He decided against divulging any further details.

He wasn't ready to share too much with Snape until he knew exactly what Tracey was up to. The staffroom teapot was a testament to the fact that Snape tended to immediately reject any outside interference in Slytherin affairs once he caught wind of it.

Anthony continued his questioning. "A kind of stone that reflects a strange blue-white light, fairly large."

"I fail to see why I should answer if you can't provide a valid reason," Snape retorted, as a small hourglass on his desk shrieked.

He waved his hand irritably, silencing the hourglass, and began adding more ingredients to his cauldron. "Moonstone. Supplement your common sense, Anthony, and you'll find it's not that difficult."

Anthony realized he now knew the names of all the ingredients in Tracey's inventory. The next step was to deduce their combinations and determine what she was secretly brewing. Whatever it was, it couldn't be beyond the scope of Hogwarts textbooks – she was only a second-year, after all, and the ingredients seemed relatively basic.

"I have no further questions. Thank you," he said.

"Very well," Snape replied without looking up. "Allow me to remind you that two of the answers I provided were incorrect. You can try to discern which ones."

"What?"

"You heard me, Anthony," Snape said. "Apply your common sense."

The potion in the cauldron turned a vibrant blue. Snape tapped the edge with his wand and stood up, a smug look on his face. "Or, you could simply tell me why you want to know about these ingredients. A very intriguing selection, Anthony. You could concoct some fascinating things with those..."

"Like what?" Anthony prompted.

Snape sneered.

"Thank you," Anthony said, opening the door and leaving without hesitation.

Snape called after him, "For Merlin's sake, who are you covering for? With those rudimentary ingredients." He wore an expression somewhere between disdain and contempt. " It's impossible to brew anything significant. A Slytherin student, I presume?" He sighed loudly in exasperation. "I believe I'm still the Head of Slytherin House, Anthony."

Anthony took this as a roundabout way of saying, "I still care about my students."