As David stepped out of the History of Magic classroom, he took a deep breath, trying to shake off the drowsiness that had settled over him. Professor Binns was as monotonous as ever—if more than three students managed to stay awake during his lecture, it would be considered a remarkable feat.
Just as he was making his way to the Great Hall, Professor McGonagall appeared beside him, walking briskly. "David, can you come with me?" she asked, her tone urgent yet carrying an unmistakable hint of relief.
David's mind immediately jumped to one possibility—Snape must have made a breakthrough in his research. The thought sent a jolt of excitement through him. After a quick word to Hermione and the others, he hurried after McGonagall towards her office.
"Did Professor Snape find the cause of the animal mutations in the forest?" David asked as soon as they turned into a quieter corridor.
A rare smile tugged at McGonagall's lips. "He received news this morning. He's managed to extract the substance responsible for the eight-eyed giant spiders' violent behavior."
David was impressed. Say what you will about Snape, but his skill in potion-making was undeniable.
Upon entering McGonagall's office, he found Professors Flitwick and Sprout already seated, their expressions calm but expectant. Moments later, rapid footsteps echoed down the hallway. The door was pushed open forcefully, and in walked Snape, looking as exhausted as he did triumphant. His usual pale complexion was exacerbated by the long hours he had clearly spent on his research. His black robes were slightly disheveled, and his greasy hair clumped together from neglect.
"Everyone's here?" Snape asked, scanning the room before his lips curled into a satisfied smirk.
McGonagall began to speak, but Snape dismissed her with a wave of his hand. He was far too eager to share his findings. Reaching into his robes, he pulled out a small vial filled with wisps of red gas, swirling eerily within the glass container.
"This," Snape declared, shaking the vial slightly, "is what caused the creatures to go mad. It lingers in the bloodstream of the eight-eyed giant spiders, heightening their aggression and driving them to attack indiscriminately."
Everyone's eyes locked onto the strange substance. The crimson tendrils inside the vial seemed almost alive, moving in distinct, sinuous patterns.
McGonagall examined it in the light. "Was there a significant amount of this gas in their bodies?"
"Not much," Snape admitted. "I've conducted multiple tests—only a single strand of it can be extracted from one spider."
Professor Flitwick, ever the logical thinker, raised a question. "If we remove this gas, will the affected animals return to normal?"
Snape's expression darkened. "Unfortunately, it's not that simple. The only way to remove it is by killing the infected creature and draining its blood. There's no other known method."
Flitwick's shoulders slumped slightly in disappointment.
McGonagall continued shaking the vial, watching as the gas briefly coalesced before splitting apart again. "Do you know what it's made of?"
Snape's lips pressed into a thin line. "Not yet. I've never seen anything like it. It must be a newly developed mixture."
Turning to David, McGonagall asked, "Have you ever come across something like this in Newt's notes?"
David took the vial, scrutinizing it as he mentally combed through the extensive knowledge he had gathered from Newt's teachings. Unfortunately, nothing rang a bell.
"Can we open it?" he asked.
Snape hesitated but eventually nodded. "Be cautious." He also drew his wand, his posture tense.
The fact that Snape was being so wary made David slow his movements. Carefully, he removed the cork.
In an instant, the red gas came to life, writhing like a nest of serpents. It shot out of the bottle, curling around David, eager to escape its confinement.
Snape acted immediately, flicking his wand. A transparent barrier enclosed the gas, and just as suddenly as it had moved, it froze in place once more.
"Are they... alive?" David asked in awe.
"We don't know yet," Snape admitted. "But they are certainly drawn to living beings."
"Would they affect people too?"
"No volunteers so far," Snape sneered.
McGonagall swiftly took the vial from David, as if worried he might get any reckless ideas. "Professor Sprout, do you recognize this substance?"
Sprout studied it for a moment before shaking her head. "I've never seen anything like it."
McGonagall sighed. "Severus, can you isolate its components?"
Snape nodded curtly. "I can try. If I succeed, I may be able to formulate an antidote."
Before they could discuss further, a loud knock interrupted them. The door rattled under the force, as if someone was trying to break it down.
Snape's expression darkened as he yanked it open. A breathless student stood outside, drenched in sweat, leaning against the wall as he struggled to catch his breath.
"What is it?" Snape snapped impatiently.
The Slytherin student swallowed hard, his face pale with fear. "Professor… the mermaids in the Black Lake—they've gone mad! They're attacking the windows of our common room!"
Snape's pupils dilated in shock. "How long has this been happening?"
"Almost half an hour," the student stammered. "The windows are cracking, but we couldn't find you. I just heard you were here and ran to tell you."
Without another word, Snape stuffed the vial into his pocket and stormed out, the student scrambling to keep up. The other professors followed in hurried strides, David close behind.
When they reached the Slytherin common room, a large crowd of students had gathered, whispering anxiously. Snape wasted no time.
"Be quiet!" he commanded, and the corridor fell into an uneasy silence.
He stepped forward and muttered, "Pureblood." The stone wall shifted, revealing the entrance. Striding inside, he was met with a chilling sight.
Through the submerged windows of the common room, dozens of mermaids loomed, their ghastly faces pressed against the glass. They brandished tridents and makeshift weapons, their red eyes gleaming with unnatural rage as they pounded against the windows with alarming force.
A sharp crack ran through one of the panes.
"They're infected too," McGonagall whispered grimly.
Snape raised his wand. Ice began creeping up the glass, reinforcing it, but McGonagall stopped him sharply. "You cannot harm them! Dumbledore has an agreement with the merfolk."
Snape's jaw clenched, his frustration evident, but he obeyed.
Before they could decide on a course of action, the mermaids suddenly parted, making way for a massive figure. A burly mermaid, crowned and wielding a trident, swam forward.
With a sinister grin, he lifted his weapon and brought it crashing down against the glass.
Light exploded from the impact.
The reinforced windows shattered, and torrents of Black Lake water surged into the room.
McGonagall and the other professors raised their wands, forming a barrier to hold back the flood, but it wouldn't hold forever.
"David!" McGonagall yelled over the roar of water. "Find the other professors—quickly!"
Without hesitation, David turned and ran, weaving through the chaotic corridor. He needed to act fast.
And Hogwarts, once again, teetered on the brink of disaster.