...Back to when Harry and Ron carried Neville back to the dormitory...
"Wow Harry, when did you learn that move? It's awesome!" Ron praised. Though they felt bad for well-meaning Neville, that Leg-Locker Curse was really cool.
They hadn't meant to trap Neville with the curse - they didn't want to involve their friend, since where they were heading had Snape, a cold-blooded killer (in their eyes).
Harry scratched his head embarrassedly at Ron's praise. "It was in our Charms textbook. I hadn't noticed it before, and didn't expect it'd be so simple to learn. But Ron, have you figured out how to open that door?"
Ron perked up at this, confidently answering: "Of course! I found a spell too - the Unlocking Charm. You know, the incantation goes... Alohomora? No wait, it's Alohomora."
He clearly wasn't very practiced, but under Ron's repeated assurances, Harry's worries lessened somewhat.
Hope they wouldn't fail before even getting through the outer door.
As they approached the door containing Fluffy the three-headed dog on the fourth floor, both grew nervous. After all, they had to find a way past Fluffy before they could get the Stone ahead of Snape.
Or perhaps Snape had already beaten them to it and taken the Stone, meaning they'd have to face that terrifying killer (in their eyes).
Maybe Snape himself didn't realize how "highly regarded" he was in Harry and Ron's minds.
If he knew...
Potter and Weasley slandering a professor - 30,000 points from Gryffindor!
They finally reached the locked door. Harry nervously watched Ron's glowing wand, silently praying for him.
Merlin, please let Ron succeed just this once!
Ron was sweating profusely - he'd tried over ten times with no effect on the lock. He'd never regretted not paying attention in class more.
Fortunately, perhaps because Merlin had put on new stockings today and was in a good mood, after many attempts, Ron's Unlocking Charm finally worked. The lock clicked open.
They exchanged glances, both seeing joy in each other's eyes.
"Got everything?" Harry asked nervously.
"Of course." Ron mysteriously rummaged in his robes, replying softly.
"Is it genuine?" Harry still looked worried.
"Trust me," Ron patted his chest and pulled out a music box, saying painfully: "I used up my pocket money renting this from George and Fred. If we're careful, maybe we can return it intact."
This was their plan for dealing with Fluffy - they'd overheard Hagrid and Glenn's conversation about how the three-headed dog would fall asleep at music.
They carefully pushed open the door, peering in stealthily until they saw someone playing a harp.
Their faces changed - they'd thought the locked door meant Snape hadn't acted yet, but now it seemed that wasn't the case!
Wait, bro, you lock the door after stealing something? How considerate!
Below the trapdoor at the end of the obstacles, the crippled Voldemort staring at the Mirror of Erised sneezed heavily, blood and flesh spraying from his missing right half, making his already pale face even whiter.
"Damn, is this body reaching its limit? But how do I get the Stone out of this damned mirror?" He growled angrily in a low voice, but his expression soon relaxed. By his timing, that Harry Potter should be arriving soon.
While hiding, Voldemort had learned through his methods that the Boy Who Lived would also come here tonight. When he did, Voldemort could capture him to retrieve the Stone, or at worst, kill him here to avenge the rebounded Killing Curse.
Voldemort glared hatefully at the crowbar in his hand. He'd found this item in the black market long ago, supposedly called the... Holy Sword of Physics or something - an unfamiliar name but impressive-sounding. Though he hadn't discovered its special use, it should work fine for smashing a child's skull.
You can't reflect physical attacks too, can you Potter!
In the end I'm still superior, hahaha!
Voldemort's suppressed maniacal laughter echoed at the obstacle course's end.
Back to Harry and Ron - seeing Fluffy already asleep from Snape's harp, they simply left their music box aside and searched the space for a while, finding nothing unusual.
Finally sharp-eyed Ron spotted a trapdoor under Fluffy's massive paw.
This was the only way - definitely the right direction.
After telling Harry, they used all their strength to move Fluffy's paw.
Both red-faced from effort, just before they nearly passed out from exertion, they finally moved the paw off the trapdoor.
But the movement had started to wake Fluffy, and worse, the harp chose this moment to stop playing.
Fluffy woke, his sleepy eyes immediately spotting two small figures moving below him. He began barking furiously, nearly making Harry and Ron wet themselves.
They hurriedly opened the trapdoor, staring into the bottomless vertical space and gulping.
"No choice but to jump! Harry, you jump, I jump!" Ron said heroically. Fluffy couldn't bear to watch and swatted them down with one paw. As Ron fell, he horrifically realized Fluffy's paw had crushed the music box he'd left aside!
"Nooo!!!" Ron's scream faded into the trapdoor - hard to say if he was more scared or heartbroken.
Falling, constantly falling - just as they were screaming madly, thinking they'd become Harry and Ron paste, they landed.
"Oh, it's a soft landing!" Harry's held breath released in relief at surviving, telling Ron beside him.
The latter had a devastated face, lifeless eyes mumbling: "The music box, my music box..."
But soon they noticed something odd - these black, soft, slippery things beneath them were moving, gradually wrapping around their bodies.
Ron instantly snapped out of his music box grief, screaming in terror: "What is this?! It's wrapping around us and tightening!" Harry reacted similarly, both struggling desperately as strange sounds occasionally echoed in the space - things like "No!", "Not there!", "Ah!", "That's not allowed!"
Soon their cries for help vanished into the black vines.
Harry and Ron were wrapped so tight by the Devil's Snare they couldn't breathe and passed out - failed before beginning.
Ah they weren't dead! Professor Sprout wasn't that cruel - this Devil's Snare was more sensitive than normal, loosening its grip when it sensed the two unfortunate unconscious victims. Harry and Ron's limp bodies gradually slid free of the Devil's Snare's range.
But they remained seriously injured (not really)
...
"Why aren't they here yet? Does the Boy Who Lived need this long for such simple obstacles?!" Voldemort's face darkened, growing impatient as his body was nearly at its limit.
He decided to go grab Harry Potter directly.
Quickly passing through those obstacles back to the starting point, Voldemort was speechless.
Harry and another boy lay sprawled on the ground - Voldemort immediately knew what they'd encountered.
Even someone as cold-blooded as Voldemort couldn't help his twitching mouth.
This guy killed me once?
I refuse to accept this, damn it!
Face black, he kicked Ron aside and used Aguamenti to wake Harry.
Harry drowsily opened his eyes to vaguely see a black-robed figure spraying water at him, instantly enraged.
"Snape! Kill me if you want, but you can't humiliate me like this!" Harry cried indignantly. Being choked unconscious was embarrassing enough, now he had to suffer such disgrace - he felt like killing himself.
Then he glared angrily at the figure but froze.
This wasn't Snape!
But who was this snake-faced person missing half his body?!
"Who... who are you?!" Harry jumped up suddenly, but rose too fast, got lightheaded and fell again.
"You should know, Potter boy - I am Lord Voldemort." Voldemort couldn't be bothered with suspense, he was nearly dead and didn't want to waste a moment, reaching for Harry's neck.
Harry's brain crashed hearing Voldemort's name.
What's happening? Why Voldemort?? Where's Snape? What happened to my big Snape?
Harry was dumbfounded, unable to react to Voldemort's reaching hand.
By the time he noticed, it was too late.
Harry watched in horror as Voldemort's hand gripped his neck.
He closed his eyes in despair, feeling his life was over.
With the cold sensation on his neck and a scream, Harry couldn't help opening his eyes.
He saw Voldemort staring in horror at his own hand that had reached out.
It was covered in blisters, as if burned.