That strange gray fog hovering over the Dementors and Boggarts was like a storm cloud sinking from the sky, forcefully shoving aside the pale mist the Dementors gave off. It rolled and spread without end, growing thicker and denser in the boundless space.
Lupin seemed unfazed by the chaos around him. His wand aimed at the full moon—and the savage wizard beside it—as he fired off two spells in quick succession.
"Expecto Patronum!"
"Riddikulus!"
Crack…
With a deafening snap, the Defense Against the Dark Arts professor poured everything into the attempt—like a circus lion tamer cracking a whip at a defiant beast.
The wall of white mist tore open.
His silver wolf Patronus charged, whipping up a gale that ripped through the fog, clearing just enough space for the Riddikulus charm to hit.
Fenrir Greyback's eyes widened. The feral glare turned to confusion. The patchy fur on his cheeks and head grew, then faded—turning fluffy. His exposed fangs and claws shrank back. In seconds, the brutal werewolf became a tiny Chihuahua.
Lupin turned, breathing deeply, his face still grim.
The Greyback Boggart was handled, but the full moon hung untouched, its light growing brighter, bathing everything in cold silver.
It looked similar to a Patronus glow, but felt completely opposite. A Patronus brought calm and safety. This moon—fed by fear—seemed to light the way for monsters in the shadows, chilling the heart.
In another direction, Sirius and Snape faced the same nightmare.
Shattered doors and windows. Glass snowing down. A chandelier crashing from the ceiling. James's body sprawled on the floor. Lily pleading desperately. It was the Potters' cottage thirteen years ago.
But the ending was fixed. Green light flashed. The green-eyed witch collapsed onto the rug, eyes wide open in death.
"No… no…"
Sirius's cracked lips trembled, eyes red. His words slurred.
Even knowing it was a fake—a Boggart feeding on his fear—seeing James and Lily die in front of him broke him all over again.
"…"
Snape stared at the shifting scene, face blank. Only his white-knuckled grip on his wand betrayed him—veins standing out under the skin.
Sensing their fear, the repeating vision changed.
On the rug by the white crib, the two bodies rose. Empty eyes turned toward the source of the terror.
"Sirius!"
The male corpse called out, voice piercing—like a demon from hell.
Sirius shook, hypnotized by that face. It was James—exactly as he remembered, the friend he'd dreamed of for thirteen years.
James's expression twisted with hate. "Why did you betray me? I trusted you completely—made you Secret-Keeper, put my family's lives in your hands. My wife, my son… you destroyed everything!"
"It wasn't… it wasn't like that…" Sirius backed away, meeting those eyes. "I thought it would be safer…"
"You couldn't handle the responsibility! I despise your cowardice, your stupidity, your weakness…"
Sirius raised his wand shakily. Magic sparked at the tip, but the words wouldn't come. The Boggart-James's voice drilled into his skull, making his head spin.
On the other side, the Lily-Boggart locked eyes with Snape. She was even more beautiful than he remembered—those green eyes reflecting moonlight, almost hypnotic.
She didn't scream or curse. She just whispered, voice trembling:
"Sev… Severus…"
The Dementors and other horrors blurred. Snape froze, staring through the mist. He could almost see the resentment in those eyes—mixed with anger. One look stopped his heart.
It was as if guilt, built up over years, now flowed through his veins instead of blood—thick as mud from the bottom of the Black Lake, rotting and foul.
Snape snapped out of it, rage surging.
"That's her face, her voice… How dare you? How dare you!"
The Potions master slashed his wand. The spell cracked like thunder.
An invisible lash tore through the fog, striking the Boggart's core. The fake Lily dissolved into wisps. The whole Potter cottage began to collapse—walls cracking, ceiling crumbling.
"How did you—?" Lupin stared.
"Occlumency," Snape muttered, not bothering to explain.
Lupin remembered. Back in third-year class, Professor Lewin had demonstrated it—shutting your mind to block a Boggart's probing, cutting off the illusion at the source.
Not only that—the young professor could even plant false memories, turning the fear-eating creature into a toy, making it change into whatever he wanted.
He'd used the same trick to help heal the Longbottoms' trauma.
Snape couldn't whip up perfect fake memories on the spot, but he could fake it enough for this.
"Sirius—calm down. Use Occlumency to block the Boggart. Don't let the illusions get to you," Lupin called. "Harry, you three—stay calm. Leave this to us."
Harry opened his mouth to ask something, but the white mist rolled over them, cold dread seeping into his bones.
A Dementor-Boggart zeroed in on him. Its cloak swayed. Pale, skeletal hands reached slowly. The breathing hole rasped heavily.
Harry raised his wand instinctively, hesitated—Riddikulus or Patronus?
Whatever.
"Riddikulus!"
Crack!
The Dementor-Boggart froze, arms flung wide like it was nailed to a cross. Straw bulged under the cloak. A bright floral bonnet appeared under the hood.
No flashy Patronus charge, but the simple Riddikulus worked—keeping Harry's Boggart at bay.
"If only the Patronus Charm were this easy," Harry muttered, swinging his wand nonstop, firing Riddikulus after Riddikulus, scattering the fake Dementors.
But more shadows swarmed—like they condensed from the mist itself, endless. Pale hands flailed like a horde of corpses.
That was the problem with Riddikulus—one Boggart at a time.
Harry barely had time to think. Spell, swing, repeat. If the end-of-year practical included Riddikulus, he'd ace it.
It worked great—each crack turned a Dementor into a scarecrow, straw and floral fabric spilling out.
The scarecrows melted back into the mist, probably reforming for another attack. Clear one, and more poured in, gliding closer.
Sometimes a face peeked from under a hood—empty eye sockets trailing gray mist, just two holes for a nose, a sucking mouth straight into the skull. Like a monster molded over bone.
Harry's wand moved faster—less than a second between spells. But in that second, cloaks closed in.
Hands reached his face—glowing faintly, pale and scabbed, like something long dead and waterlogged.
His stomach churned. His tongue stumbled on the incantation.
That tiny pause was enough. The mouth under the hood quivered. It drew a long, rattling breath.
Harry's eyes rolled back. Consciousness sank into dark water.
This one wasn't a Boggart. It was a real Dementor.
The moment his defense slipped, the Dementors swarmed like sharks smelling blood. They paused, then rushed Harry with horrifying sucking noises.
"Severus!" Lupin shouted. He and Sirius were tied up on the other side.
Bright silver flared. Without looking, Snape swept his wand in a wide arc. A silver doe leaped through the air, hooves flashing, charging the shadows and clearing space.
"A doe…"
Sirius blinked, stunned.
Lupin glanced over, thinking: No wonder Dumbledore trusted him.
Snape pressed his lips tighter, silent.
Harry barely caught his breath when Ron let out a hysterical scream: "Riddikulus…"
Only then did Harry and Hermione see Ron's nightmare shift. Sensing his panic, the Boggart swarm changed tactics. The giant spiders clacked backward, making room for grinning rats to push forward.
Bald, missing-toed rats—one after another wearing Peter Pettigrew's face, squeaking in high voices about old times.
"Ronnie! Ronnie! You'd really abandon me?"
"We shared the same Chocolate Frog—you didn't even mind my bite marks!"
"Those sleepless summer nights—I kept you company. You told me all your troubles!"
"…"
"I'm not—I didn't—get away from me!" Ron went white, screaming and swinging his wand.
Then a big ginger cat barreled in from the side. Sharp claws slashed clean arcs—one rat head torn open. A kick crushed another. Fangs sank into a neck, shaking viciously.
The flat-faced cat tore through the rat pack like a savior from above.
"Crookshanks!" Ron yelled.
"Crookshanks?" Hermione blinked.
"False memory charm!" Lupin called, directing his wolf Patronus against the Dementors. "Lewin's trick—I fooled the Boggart into thinking it's Crookshanks, helping chase the rats."
It was fake, but even a Boggart-Crookshanks did the job—mercilessly slaughtering rats, ginger fur bloodied, majestic as a knight in armor.
Ron stood frozen, almost in tears, speechless.
Sirius managed shaky Occlumency. Lupin and Snape combined false memories to control Boggarts while shielding the kids. Their Patronuses—a dog and wolf—cleared huge swaths of Dementors. Things stabilized.
They carved out a safe pocket amid the monsters, slowly retreating the way they'd come, glancing nervously at the gray fog outside.
The real terror was whatever brewed out there. Boggarts and Dementors had counters. But that shapeless thing—even the Dementors avoided it.
Faint red glimmers flickered inside the gray—like eyes blinking slowly.
If Boggarts embodied fear and Dementors drained joy and souls, this fog felt like pure despair and self-loathing, hating the whole world.
At some point, the Dementor attacks slowed. Unexpectedly, the professors cast more easily. Snape dismissed his doe—dog and wolf alone held the line.
The Boggarts were still thick overhead.
"Lupin's Crookshanks idea for me, Dementors for Harry, spiders and Peter for me," Ron said suddenly. "Hermione—you don't know Occlumency either. What would the Boggart turn into for you?"
As he spoke, the gray fog rolled down like a crushing wave, whipping up winds that scattered Dementors.
Hermione went pale. "It's coming."
The pressure shift tugged at their robes. They felt every inch closing in—ears popping. Then came the sickening crunch of breaking bones.
Spiders and rats—flesh and blood—were shredded as the fog swallowed them, limbs flying.
It really was a Riddikulus gone wrong. No wonder the Boggarts had built up so long. This wasn't normal magic anymore. It was the twisted power born from a young witch's childhood self-hatred—magic mutated into something monstrous.
Anything caught inside would be torn to pieces.