Everyday Life of a Top Student at Hogwarts

Chapter 320 Dark Algae Collection and Sound Wave Testing

Inside the Eagle's Nest, the atmosphere was electric after the successful verification of Slytherin's sonic manipulation technology. However, the rather large alchemical resonator was clearly unsuitable for underwater operations.

"We need to make it usable underwater." Karen stared at the device, her fingers tapping unconsciously on the worktable. "Miniaturized, waterproof, preferably handheld, or something that can be integrated into a wand."

"Integrating it into a wand is too difficult," Fabian adjusted his glasses, analyzing rationally. "It involves seamless connection of magic circuits, which can't be completed in a short time. A handheld underwater launcher is a more realistic option. We need to determine its underwater performance first, and then we can consider further miniaturizing it."

Ernesto picked up a parchment with a rough structural diagram: "The core uses a miniature resonant crystal, energy—"

Perhaps a pre-charged magic battery could be used; although the duration wouldn't be very long, it should be enough.

"This isn't too difficult. I can handle the outer casing sealing and the energy components!" Wesley volunteered, always enthusiastic about hands-on projects.

After several busy nights, including one or two minor mishaps, the first prototype of the "Portable Aquatic Organism Sound Wave Influencing Device" was finally completed. It looks like a rough black metal can, covered with a thick waterproof leather, with several adjustment knobs on the side and a small horn at the top.

"It looks a bit ugly, but hopefully it will work." Wesley weighed it in his hand.

Karen took the device, infused it with a wisp of magic, and carefully sensed the internal frequency output. "The frequency is stable, and the output intensity is about 40% weaker than larger equipment, but it should be enough to affect Grindelwald at short distances underwater. Duration—at maximum power output, it can last about ten minutes."

"Ten minutes is enough," Fabian nodded.

Having solved the tool problem, Karen didn't stop his research. Just as he had always believed, this technique of influencing biological magic through specific frequencies seemed to share some common ground with the direct resonance method of the Parseltongue—

They all bypassed normal language and acted directly on the magical or mental level. Thanks to the "Eye of Truth's" precise insight into magical fluctuations and his previous experience imitating Parsley, he began to try to simulate and emit that specific vibrational frequency directly with his own magic without relying on equipment.

This is more difficult than imitating Parsleyan speech, because at least Parsleyan speech has pronunciation and intonation to refer to, while this frequency is almost purely a magical manipulation. He often stays alone in a soundproof corner of the Eagle's Nest, closes his eyes and concentrates, emitting an extremely low, almost inaudible hum from his throat, his fingertips swirling with a faint magical glow as he constantly adjusts it.

"You've been acting strange lately, Karen," Wesley couldn't help but say during a dinner. "You're always whining to yourself, like you're struggling with something."

"A new exercise," Karen replied simply, without elaborating further. He felt himself getting closer to his goal, though he was still far from being able to perform it independently without relying on equipment. However, this understanding itself deepened his knowledge of Slytherin techniques and Parsley.

A few days later, they believed they were ready and began to develop a detailed plan for collecting dark algae.

"The time is set for tomorrow night. The moonlight will be bright, and underwater visibility will be relatively good, but it will also make us easier to spot, so we must act quickly." Karen pointed to a secluded spot on the Black Lake shore on the Marauder's Map. "Go into the water from here and sneak along this reef area to avoid the main areas of the mermaids' usual patrol routes as much as possible."

“Two of you will go into the water,” Fabian interjected. “Karen, you’ll be in charge of using the sonic device to keep watch and disperse any potential Grindelhos, and try to use it on the mermaids if necessary. I’ll be in charge of collecting the data. Ernesto and Wesley will keep watch from this position on the shore.” He pointed to a secluded high point on the map that overlooked a large expanse of the lake shore.

"If we are discovered, or if there is an emergency," Ernesto said seriously, "Karen, emit the red spark, and we will immediately fire a blinding spell towards the lake to temporarily disrupt the mermaids' vision. Then you should immediately surface and retreat. We have prepared ropes and lanterns to assist you."

"Although I think it's unlikely we'll need it," Karen nodded, "it's always good to be prepared." He was confident in his and Fabian's underwater capabilities, not to mention the new equipment and the sonic technology they were practicing.

The following night, the moonlight shone like mercury on the surface of Black Lake, making it shimmer. The four people arrived at the designated location silently.

"Are you ready?" Karen asked in a low voice. He and Fabian had changed into simple water jackets, but still wore wizard robes over them for disguise.

"Anytime." Fabian checked the sample bag and crystal scissors at his waist.

"Leave the shore to us," Wesley said, patting his chest. Ernesto, meanwhile, had already raised his night-vision binoculars, scanning the lake and the surrounding woodland warily.

Karen and Fabian took off their robes and handed them to their companion, took a deep breath, and raised their wands to themselves.

Two enormous bubbles enveloped their heads, providing ample air. They exchanged a glance and silently slid into the icy lake.

The underwater world was bathed in a hazy silvery-blue light from the moon. Karen led the way, with Fabian close behind, as they swam along the rugged, shadowy path of the reef. Karen skillfully guided Fabian, who was new to the water, toward their destination.

Soon, they approached the area where the dark algae grew. Karen raised his hand, signaling Fabian to stop. He stared intently; in the Eye of Truth's vision, several wisps of murky magical energy representing Grindylow were lurking in the rock crevices near the dark algae, acting as sentries. He hadn't expected the mermaids to have set up sentries; they weren't there the last time he was here. He wondered if it was because of his previous actions. Further away, several more powerful and orderly streams of magical energy moved slowly—the mermaid patrol.

Karen gestured to Fabian, pointing in the direction of Grindelwald, then raised the completed sonic device, aiming the output at the target area. He slowly turned the knob, setting the previously verified "sedation frequency a".

An invisible ripple traveled through the lake. The device vibrated slightly, and the water flow in front of the horn-shaped opening showed a subtle distortion.

The effect was almost immediate. Soon, the magical halos representing Grindelhos became noticeably sluggish and dim. Their previously restless movements slowed down, and they became somewhat confused. One of them even slowly swam out from its hiding place and wandered aimlessly for a distance.

Karen nodded vigorously to Fabian.

Fabian glided swiftly and silently toward the dark algae, like a fish swimming. He took out his crystal scissors and precisely and quickly cut off several small clumps of dark, spiral-bladed algae, carefully placing them into a specially made sample bag lined with soft velvet and enchanted with preservation and magical energy-insulating properties. His movements were clean and efficient, barely stirring up any sediment.

Karen kept the device running while keeping a close eye on the movements of the mermaid patrol in the distance; everything seemed to be going smoothly.

However, just as Fabian finished collecting the last cluster and was preparing to retreat, a sharp and indistinct hiss suddenly came from the deeper waters further away! A much thinner stream of magic, which looked like a young or small mermaid, was rushing towards them at high speed, the magical aura of the coral spear in her hand particularly conspicuous.

"We've been discovered!" Karen's heart skipped a beat. She immediately stopped emitting sound waves, made an "emergency surfacing" gesture towards Fabian, and pointed upwards forcefully.

Fabian heard the noise and, without hesitation, immediately turned around, pushed off the rocks at the bottom of the lake with both legs, and his body quickly floated upwards.

Karen didn't decide to go up now. He felt this was a good opportunity to experiment on the mermaids. He quickly slipped behind a huge rock and waved his wand to cast an illusion spell on himself. His body color quickly became one with the surrounding environment.

He saw Fabian rise smoothly to the surface, approaching the water's edge. Wesley and Ernesto on the shore had clearly also sensed the situation through the ripples on the water or a pre-arranged signal, but they did not rashly use the Light Spell, because Fabian was already rising and no larger number of enemies had appeared.

The merman who had rushed over circled the spot where Fabian had been collecting samples, seemingly finding nothing amiss. It then looked towards the direction where Karen was hiding, appearing puzzled as to why the anomaly it had sensed earlier had vanished. After a moment's hesitation, it began to patrol in a larger circle.

Karen held her breath and waited patiently. After a while, two more, stronger merfolk swam over, seemingly summoned by their companion. They exchanged a few words, making those gurgling hissing sounds, and together expanded their patrol area. Just as Karen had expected, the merfolk began to disperse, making it easier for Karen to conduct her experiment without disturbing them.

Karen saw an opportunity when one of the mermaids, seemingly separated from its two companions due to expanding its patrol area, swam towards the side and rear of Karen's hiding place. Karen quietly peeked out from behind the reef, aimed at the lone mermaid, and activated the device again, this time fine-tuning the frequency to target the mermaid.

The vibrations from the device reached the merman. It paused noticeably, its tail swaying hesitant, and its wary expression seemed to relax slightly, though not as dramatically as Grindelwald's. It shook its head, looked around, seemingly confused, but not completely let down its guard or become dazed. The effect seemed more like a gentle reassurance and disturbance than control.

"Limited effect—" Karen noted the result in his mind. "For creatures with higher intelligence, especially races like mermaids that have a certain resistance to magic, it mainly serves to interfere and confuse. Its control is very weak, but the fact that it is effective means that we can continue to study this method in more depth."

He then tried to briefly affect two other mermaids a little further away, with similar, or even weaker, effects. They experienced brief discomfort and confusion, but quickly recovered and became more alert, searching their surroundings.

Having collected enough data, Karen didn't linger. He silently retreated, moving away from the mermaids' patrol area, before quickly surfacing.

With a splash, he broke the surface of the water and took a deep breath of the cool night air. Wesley and Ernesto immediately reached out from their hiding place on the shore and pulled him up.

"Are you alright?" Wesley asked anxiously. "Fabian is back, and we got the samples."

"I'm fine." Karen wiped the water from her face. "I just took the opportunity to test the device's effects on the mermaids. Where's Fabian?"

"Here it is." Fabian emerged from behind another rock, having dried himself off and put his robe back on, clutching the sample bag tightly in his hand. "The collection went smoothly; the amount is sufficient for our initial research."

"How's the effect? ​​Is that black jar effective?" Ernesto asked curiously.

"It worked very well on Grindelwald," Karen said, drying her hair with a towel as she changed back into dry clothes. "It had some effect on the mermaids—but mainly it disrupted and confused them, slowing their reactions and making them a bit bewildered. It's difficult to completely control their actions. But that was to be expected."

"It's good that we got what we wanted." Wesley breathed a sigh of relief. "Not having to fight is a victory in itself."

Under the cover of moonlight and the Disillusionment Charm, the four quickly left the lakeside and returned to the castle. The operation was successful without incident, and they even obtained valuable data on the combat effectiveness of the sonic device.