Just as Voldemort said, breaking the Sleeping Curse was followed by the Curse of Undeath.
But this wasn't true immortality.
Instead, it was a product of Dark Magic, similar to Inferi.
The attacked Acromantulas were like lifeless mechanical puppets.
Except for wounds inflicted by the holy magic of Unicorns...
All others regenerated after a flash of black light.
Dumbledore turned his head to look at the source of the spiders, the Acromantula habitat.
At the cost of putting other magical creatures to sleep, Slytherin's authority connected and "burned" Malfoy's body, bringing forth a powerful hypnotic force. After the Sleeping Curse was broken, it didn't disappear.
It was more like a terrifying chain reaction occurred.
The dreamlike magical magnetic field, which had merely hypnotized their minds, now turned eerie and evil.
Using that web-covered sunken ground—the Acromantula nest—as the source, it transmitted to every single Acromantula.
In that instant just now, all the spiders were cursed to death.
The life-filled magnetic fields of living creatures on their bodies turned deathly silent.
Most of the students on the grounds had already returned to the castle.
With the defensive line Dumbledore set up, there was little use for them to stay here.
But adventure-seekers like the Weasley twins, as well as Basil and his group, remained.
The professors in the castle gathered the students in the Great Hall.
To avoid a repeat of Hermione's mix-up during Christmas, they specifically had the prefects do a headcount.
They knew someone was after the Philosopher's Stone, someone who had broken into Gringotts for it.
The Troll at Christmas and everything happening today were likely the work of that same person.
According to Dumbledore's instructions, that person should have also gone to the forbidden corridor on the fourth floor.
Snape was sent there for this very reason.
And Dumbledore's other instruction—protect the students—suggested that the Dark Wizard might have other ways to buy time, through terror attacks.
So, the plan to send students back to their common rooms or station them in the three highest towers—Ravenclaw Tower, Astronomy Tower, and Gryffindor Tower—to cast defensive magic and observe was rejected.
Instead, they chose to use the Great Hall as a stronghold and build fortifications.
Professor Flitwick pointed his wand at the open castle doors and muttered extremely complex incantations in a low voice.
Everyone heard a strange whooshing sound, as if he had unleashed the power of the wind onto the grounds.
"Hogwarts is under threat!" Professor McGonagall said loudly. "Man the boundaries, protect us, do your duty to our school!"
With a clatter and shouts, a group of moving statues swarmed out of the Great Hall—some slightly smaller, some larger than life-size, and some animals.
Clanking suits of armor brandished swords and chained maces.
Professor Sprout went to the greenhouses, waving her magic to place various dangerous magical plants on the grounds: Venomous Tentacula, Devil's Snare, Snargaluff pods...
"Do we really need to go this big?" Basil looked around helplessly.
He wanted to show off.
In his plan, he would lower his wand.
Walk into the spider swarm and say: "Harry, Ron, do you remember how my parents died?"
"I said then I didn't care, not entirely because I had never seen them alive."
"But because that Death Eater was also killed by my father in return. I have no living enemies."
"In the forest, a Granger, even one on the brink of death, is terrifying."
Then with a wave of his hand, thousands of branches and silky grasses would heed his command and attack the spider swarm.
But now, what the hell could he do?
Hermione, Harry, Ron, and the Weasley twins around him shared the same thought.
If they had known this, they might as well have returned to the castle.
In front was Dumbledore's golden line; Flitwick's wind defense surrounded them; statues and armor guarded the perimeter; various magical plants were hidden in the gaps and grass.
With this comprehensive defense and troop deployment, they even dared to camp and sleep right there.
According to Dumbledore, it was only cursed Acromantulas.
If not for the curse, which only Dumbledore could lift, he could probably handle it with a single Fiendfyre spell. Just like Dumbledore's lover, Grindelwald, could burn down all of Paris with one blue fire spell.
But the next second, Basil, who had been monitoring Voldemort/Quirrell's progress, couldn't hold his expression.
Is Narcissa okay?! (Implying: Lucius is dead, so is his wife okay?)
He heard the news of Lucius Malfoy's death and the even more terrifying message about the Curse of Undeath.
Sure enough, as soon as Voldemort finished speaking...
The Acromantulas, glowing with black light, passed directly through the golden line.
Those mangled limbs that hadn't been incinerated began to reassemble automatically, and Acromantulas emerged again one by one.
The wind in front of Basil and the others turned brutal, tearing apart any approaching spiders.
Statues and suits of armor clashed with the spiders that reformed after being torn apart.
The poisonous plants among the magical flora, which should have been the most dangerous, posed the least threat to these dead things, only able to do some auxiliary work with the strength of their vines and branches.
Some strange plants whose functions Basil didn't know actually performed great deeds.
For example, to the front left, a plant only a foot high with a pink stem and an end like a cotton ball wrapped lollipop.
Once a spider approached, the cotton ball would shoot out, expanding in the process, finally wrapping up the horse-sized spider.
Others secreted a transparent, gelatinous liquid, projecting "liquid balls" through self-waving branches, sticking the incoming Acromantulas to the spot.
Even more amazingly, these plants seemed to have their own consciousness, avoiding Basil and the others still on the grounds, attacking only the spiders.
Basil suspected that the predecessor of the Granger family's [Plant Affinity] talent—spells to control plants—was known to Professor Sprout. After all, she was the Head of Hufflepuff, and Helga Hufflepuff was the founder most proficient in Herbology and Earth magic among the four. The Hufflepuff common room was full of plants.
In short, the undying swarm of Acromantulas brought by the Curse of Undeath still hadn't broken through the defense line.
Basil and the others still had nothing to do.
Hagrid, who should have noticed everything on the grounds, was still slacking off inside the suitcase, playing with the dragon.
Dumbledore also walked into the dark, deep spider nest. The silver Phoenix Patronus merged with Fawkes, turning the giant spiders trying to bypass Dumbledore toward the castle into flying ash.
The Patronus's holy magic dispelled the Curse of Undeath spreading on these spiders.
This was also why the defense line on the grounds hadn't been breached.
More Acromantulas were here, illuminated by the holy brilliance released by Fawkes, scattering into dust and merging with the dead branches and rotting leaves.
The old, dead Aragog, the source of the Curse of Undeath, retreated deeper into the Forbidden Forest with the help of his equally dead offspring.
Although dead, the residual instincts of their flesh interwoven with the Curse of Undeath made them subconsciously want to stay away from that holy magic... and the demonic magical magnetic field beside it—hot as fire, loving everything but itself, only burning without rebirth—which could not be ignored.
But it was all in vain.
Under the approach of Dumbledore, who fully revealed his true self, the movements of the giant spiders deep in the nest slowed down.
Light descended into the dark hollow; black smoke clouds accompanied by flying sand vanished into the air.
Solving the Curse of Undeath was only a matter of time.
Meanwhile, in the forbidden corridor on the fourth floor, in the final room beneath the trapdoor, Quirrell unwrapped his turban, turning his back to the Mirror of Erised.
"I show not your face but your heart's desire. A laughable trick," a cold voice said in a mocking tone.