"Professor Lupin, Dementors aren't classified as magical creatures. They don't obey humans, not even wizards, and their relationship with the Ministry is more of a loose alliance than anything else."
To prove his point, Dudley commanded, "Get me a glass of water."
The creature, which Lupin suspected might be a Dementor but was actually a Boggart, obediently glided to the side, poured a glass of water, and handed it to Dudley.
Dudley took the glass but didn't drink. Instead, he set it aside.
"See, Professor? It's definitely a Boggart."
Lupin completely ignored Dudley's explanation. His eyes were fixed on the glass. The water inside was visibly decaying at an alarming rate. In mere seconds, it turned murky, and a layer of frost formed on the surface.
Lupin: ???
You're telling me this isn't a Dementor's doing? That's textbook Dementor behavior!
"Professor, the Dementors are outside the castle, searching for Sirius Black. There's no way they'd be inside Hogwarts, nor do they have any reason to be," Dudley added suddenly.
Lupin froze, caught off guard by the comment. Having spent years on the run, he understood what Dudley meant.
He was right—Dementors couldn't be inside Hogwarts. The castle was free of them, so this had to be a Boggart.
In the end, whether it was a Dementor or a Boggart didn't really matter. What mattered was what they needed for the Defense Against the Dark Arts lesson.
"Can it really handle the job? It won't attack anyone, will it?" Lupin asked, eyeing the "Boggart" with a hint of concern.
Dudley's response was brimming with confidence. "Don't worry, it'll be a perfect teaching tool."
The ones that weren't perfect are already Philosopher's Stones by now.
During the Quidditch match, hadn't Dudley captured over thirty of them? Sure, they weren't magical creatures, so he couldn't tame them with system skills. But Dudley had used the oldest, most straightforward method of taming—physical persuasion.
This one was the last of the bunch he'd caught that day.
Turns out, low intelligence has its perks. At least after some physical persuasion, betrayal wasn't an issue.
Dudley had named this sole survivor "Soulhook." Yep, a Boggart, hit with a Confundus Charm to resemble a Dementor, now called Soulhook.
"As long as it cooperates, I think our lessons will move along much faster," Lupin said with a nod.
Practical experience was always the best and fastest way to learn.
"So, who wants to be the first to give it a go?" Lupin turned to the other young witches and wizards.
He needed a volunteer, ideally someone whose Patronus Charm was close to taking shape.
The students exchanged glances, but no one stepped forward. A Dementor—even one that was just a Boggart—wasn't something you could just tackle on a whim.
It carried real risks, far more dangerous than the dark creatures Lupin had used in past practical lessons.
Draco scanned the room. He figured he should step up. His Patronus Charm was this close to forming. Was there anyone in the room more qualified than him?
The spotlight should belong to a Malfoy.
Clearing his throat, Draco started, "Ahem, Professor, I—"
"I'll do it," Harry cut in, stepping forward before Draco could finish.
Like Draco, Harry's Patronus Charm was nearly complete.
Lupin didn't hesitate. "Excellent, Harry. You'll be our first demonstrator."
Lupin always kept a close eye on James's son. Harry was exceptionally skilled at handling dark creatures, second only to Dudley in mastering Defense Against the Dark Arts material.
"Stand over there," Lupin said, clearing a space for Harry to work.
"Remember, Harry, when casting the Patronus Charm, focus your mind and think as hard as you can about a happy memory."
After stressing the importance of the spell's execution, Lupin stepped aside, leaving Harry to face the "Dementor."
Dudley gave a nod, and the creature glided forward. The moment it reached Harry, the classroom's lights flickered and went out. The young witches and wizards held their breath, craning their necks to watch.
The Slytherins thought to themselves, "Asking a dark wizard like Potter to cast a Patronus Charm? That's a tall order. Now, if it was one of the Unforgivable Curses, Potter would nail it, no question."
Harry took a deep breath as an icy chill washed over him, his breath turning to white mist.
Think of something happy.
He silently repeated the mantra, slowly raising his wand.
Closing his eyes, his mind raced, memories flashing before him like a series of photographs.
Finally, a few images locked into place, and Harry shouted, "Expecto Patronum!"
First image: Trapped with other kidnapped children in a rundown shack, feeling hopeless, until Dudley, like a hero, kicked down the door and stood before him.
Second image: A newly renovated room in the shack, decorated just for him.
Third image: His eleventh birthday at the zoo, the sweet taste of chocolate ice cream, and Dudley goofing off, pretending to be a gorilla. Those were some of his happiest days.
Fourth image: At the seaside cottage, being held by Aunt Petunia, feeling the warmth of a mother's embrace.
Fifth image: Dudley choosing to rebuild the old Potter house into a castle, complete with a room just for Harry.
There were so many more moments like these.
With each memory, more silver threads spilled from the tip of his wand. The threads wove together, growing denser, forming a clearer image of his Patronus.
The other students watched, unblinking, as they saw a Patronus take shape up close for the first time.
Harry was completely lost in his memories.
"Stop, Harry, stop!" a slightly panicked voice called out.
Harry ignored it. It's just the Dementor's trick.
He knew Dementors could drain happiness and drag up painful memories.
Instead of stopping, Harry poured even more energy into the spell.
Until someone shook him hard, snapping him out of his trance.
"If you don't stop, the Dementor—er, Boggart—is going to die!" It was Lupin, looking at Harry with a mix of exasperation and disbelief.
Lupin hadn't expected Harry to succeed on his first try, let alone summon a Patronus so powerful it nearly obliterated the Boggart.
This training dummy hasn't even been used by anyone else yet!
Standing in front of the "Dementor" was Harry's fully formed Patronus—a massive silver gorilla, identical to the one he'd seen at the London Zoo when he was eleven.
The "Dementor," meanwhile, was being held aloft by the Patronus. One of the gorilla's hands gripped the creature's tattered robes like a collar, while the other was raised, fist clenched, ready to strike. The "Dementor" hung limply, its head tilted to one side, looking utterly defeated.