Swelling Solution, as the name suggests, can cause a part of an object to swell abnormally.
Sean didn't know exactly what situations it was commonly used in, only that—like most potions—if it was brewed or used incorrectly, the consequences could be severe.
For example, during a second-year lesson, Harry had thrown a firework into Goyle's cauldron while they were brewing Swelling Solution, distracting everyone. The potion splattered everywhere, and arms, noses, eyes, and other body parts of those hit began swelling grotesquely.
So Sean carefully watched Professor Snape's every movement, while his quick-quote quill scratched rapidly beside him.
Grind two spoonfuls of dried nettles, grind three puffer-fish eyes, mix the two ground ingredients into the cauldron, heat for twenty seconds, wave the wand…
Professor Snape's explanations often deviated from the textbook, sometimes making extensive changes—And if any young wizard dared to zone out and simply follow the book, accidents would happen easily.
That was probably one of the reasons Professor Snape was so strict, even frightening, toward the students.
"If your empty heads have finally managed to cram in some knowledge," With a wave of his wand, Snape transferred the finished potion into a crystal vial. He swept his gaze across the classroom; the students froze in silence. "Then pair up and begin!"
The classroom filled with clanging and clattering as the students nervously began brewing.
After a while, the brewing reached its final stage.
"...Process the last ingredient and continue simmering until a thin layer of white foam appears on the surface..."
Justin followed the notes anxiously, even more nervous than Sean, who was stirring the mixture.
Snape continued his patrol around the classroom to prevent any accidents.
When he reached Sean and Justin's table, his steps paused.
He glanced casually at their notes.
Heh—fairly detailed. Barely reaching the passing threshold...
"Oh, but Sean, why is our foam blue?"
Justin's voice trembled as he noticed the unexpected color.
Beside him, a dark cloud seemed to loom, making his already tense body shiver slightly.
Sean's face turned a little pale. He looked over and calmly gave the answer that made Justin nearly faint.
"Failure."
Justin didn't dare lift his head, as if bracing himself for what was coming.
"Redo it! You two idiots!"
Snape's roar came right on schedule.
Justin sighed in relief when he realized they hadn't lost any house points. Then he whispered, "You don't look well. Want to rest for a bit? I'll handle it."
After Snape left, Justin took over all the brewing work, carefully preparing the ingredients.
Sean, however, was breathing heavily. He had underestimated how much the previous potion ritual and will-guiding had drained his stamina.
Master Borach's ritual was essentially an overdraft of a wizard's magical capacity.
It allowed for a brief period of exceptional potion-brewing performance, but afterward came a period of weakness.
Just like now—he could clearly tell the problem in the final stage came from his lack of magical output.
He panted lightly and then noticed a few berry candies on the table.
"Take a break, yeah? Have some. New flavor—berries from the Scottish Highlands," Justin said, managing the bubbling cauldron while talking.
Sean nodded. He silently gauged his condition. He could still cast a few spells, but when it came to potion brewing, he was simply out of strength.
This only proved that potion-making required much higher levels of magical power and mental focus.
No wonder potion masters were so rare.
Sean also realized something else: the boost a wand and spells gave to a wizard's power was quite terrifying.
He could now cast three or four Levitation Charms in a row, and the effects weren't any weaker than potions that could make objects float.
But if he were asked to brew such a potion right now, he'd probably collapse on the spot.
As Sean silently pondered this, occasionally reminding Justin of brewing details based on the notes, Professor Snape stormed in like a tempest, holding a class roster.
"Susan Bones, Lisa Turpin—heh, troll-level ingredient handling—I suppose you didn't process the puffer-fish eyes properly."
He first sneered at the two young witches, who had brewed a thick, sticky potion.
"One point off—each. And what are you waiting for?! For the potion to brew itself?!"
Susan shrank back, nearly in tears, as Snape swept away.
"Ernie Macmillan—if you stir to the right one more time, get out! At least then the potion won't explode on its own! Two points off!"
Ernie froze, grabbed his book, and trembled as he nearly pressed his face into the pages.
"Barely acceptable—Michael Corner, what are you waiting for? For the potion to spoil?!"
Snape turned into a merciless point-deduction machine, with invisible "−1," "−2," "−1" signs practically popping above students' heads.
Sean and Justin watched Snape approach their station.
They braced themselves for the storm—yet Snape stopped for a moment, glanced at them, and moved on.
"Phew—"
Justin exhaled in relief.
Sean, meanwhile, silently stared at the crystal vial that had suddenly appeared in his hand.
Inside was a transparent liquid, with a single note attached: Drink.
...
After leaving the dungeon, Sean was still a bit dazed. That potion from Snape had only one purpose—to restore vitality.
It looked similar to a simple invigorating draught, but its effect on magical recovery was remarkable.
As soon as he drank it, Sean felt his magical reserves returning significantly, and even climbing the stairs was easier.
Back in the dungeon, Severus Snape stared for a long time at the failed Swelling Solution, which had been botched due to insufficient magical power.
On the roster in his hand, a line of text was faintly visible:
Sean Green — Guardian: None.
...
The Great Hall.
It was still filled with noise and life.
The four House tables were covered with lunch platters, and the golden plates and goblets glittered under the light of hundreds of floating candles.
Students chatted cheerfully as they enjoyed porridge, smoked bacon, and pumpkin juice.
"Sean, my mother always says: sunrise is free, and so is sunset—"
Justin poked a piece of pudding and said softly,
"So if you're tired, just rest."
His pale gray eyes shone with sincerity.
Sean silently nodded.
Until—
"Rabbit's eye, harp's melodious tune, turn this clear water into wine!"
Sean blinked in confusion and turned around. Sitting beside him was Seamus.