Swelling Solution—as the name says—makes part of something swell.
Sean didn't know exactly where it gets used; he just knew it's like most potions:
botch the brew or misuse it and the fallout can be serious.
Case in point: second year—Harry lobbed a firework into Goyle's cauldron to cause a diversion. When the brew splashed, arms, noses, eyes… all puffed up grotesquely.
So Sean watched every one of Snape's moves, while the Quick-Quotes Quill scratched away.
Grind two spoonfuls of dried nettles; grind three puffer-fish eyes; add both powders; heat for twenty seconds; wand flick…
Snape rarely followed the book—and in places outright rewrote it.
If a student drifted and defaulted to the text, accidents came easy. Perhaps that's why the professor's so forbidding—borderline terrifying.
"If your empty skulls have finally crammed in something…"
A wand flick—finished draughts decanted to crystal phials. His cold eyes swept the room; small wizards shrank into themselves.
"Pair up. Begin."
A chorus of clinks rose as trembling hands set to work.
After a while, they reached the final phase.
"…prepare the last ingredient; simmer until a white foam forms on the surface…"
Justin checked the notes, somehow tenser than Sean, who was stirring.
Snape still patrolled the room to head off further disasters. When he reached their bench, he paused—cast a casual eye over their notes. Hmph—thorough enough—barely skimming a pass…
"Oh, Sean—why is our foam blue?"
Justin's question came out tiny. A cloud loomed at his shoulder; his already taut posture trembled.
Sean's face had gone pale. He turned and, evenly, delivered the answer that made Justin's vision go black:
"Failed."
Justin dared not look up, as if bracing for impact.
"Redo—both of you idiots!" Snape's bellow came on cue.
No points docked—Justin exhaled and whispered, "You look rough—rest a bit? I'll handle it."
Once Snape moved on, Justin took over the brewing—meticulous with the prep. Sean, meanwhile, was winded. He'd underestimated the physical drain of ritual and will-guidance in the last session.
Borage's ritual felt like overdrawing one's magical credit—trading a high burst of performance for a temporary weakness.
Now the failure point was clear: he'd run short on magical output at the end.
He panted, then noticed a few berry drops laid out on the bench.
"Take five? Try these—new flavor. Berries from the Scottish Highlands," Justin said, stealing time between bubbling checks.
Sean nodded. He gauged his condition: he could still cast a few charms, but in potions he was spent.
Which meant potionwork demands more of raw magic and steely will than spellcasting. No wonder masters are rare. He also realized something else: the wand and spell advantage is terrifying.
He could cast three or four Levitation Charms easily, matching a floating potion's effect—yet brewing such a draught now would knock him out cold.
As Sean thought and murmured the next steps from his notes to Justin, a storm swept in—Snape with the class roll.
"Susan Bones, Lisa Turpin—hm—troll-level ingredient prep. I doubt you've brought those eyes anywhere near standard."
A cold sneer for the two girls with a cauldron of glue.
"One point off—each. And what are you waiting for—self-stirring potion?!"
Susan hunched, near tears; he was already gone.
"Ernie Macmillan—stir right again and get out. At least then the explosion will be outside the cauldron. Two points."
Ernie froze, dragged the book up till it nearly touched his nose.
"Barely adequate—Michael Corner—waiting for the potion to curdle?"
He became a tireless point-docking machine, little red "−1, −2, −1" flashing over heads in imagination.
Sean and Justin watched him reach their bench.
Storm due—yet Snape… stalled, and passed them by.
"Whew." Justin's relief hissed out.
Sean, though, stared at the crystal phial that had appeared in his hand—clear liquid inside, a single note on the label: Drink.
…
Outside the dungeon, Sean was still a little dazed. Snape's phial had one purpose: restore vitality.
Like a tonic—but stunningly effective at restoring magic. He'd barely swallowed when his reserves came rushing back, and the stairs no longer weighed like lead.
In the dungeon, Severus Snape stared long at the failed brew—ruined by too little magic. Faint on the roll in his hand was a line:
Sean Green — Guardian: None
…
The Great Hall.
Still a riot of life: four house tables heaped with lunch, golden plates and goblets flashing in the glow of a thousand candles. Chatter over porridge, bacon, pumpkin juice.
"Sean—my mum always says, sunrise is free, sunset too," Justin murmured, spearing pudding. "If you're tired, rest."
His light-gray eyes were sincere. Sean nodded silently.
Until—
"Rabbit's eye, harp's sweet cry, turn this water into wine!"
Sean blinked. He turned—and Seamus was sitting beside him.