Harry's heart hammered. The cavern was too quiet except for the drip of water and Naruto muttering curses under his breath. The spider shape moved closer, legs scraping stone. Its eyes gleamed like small lamps in the dark.
"Big," Naruto whispered, kunai already in hand. "Way too big."
Kakashi's voice stayed calm, but tighter than usual. "Don't rush it. Wait."
Harry gripped his wand in one hand, dagger in the other. His scar burned faint, like a warning siren that wouldn't turn off. The spider hissed, and the sound shivered through the walls.
Then—something else.
A thwip.
Thin white strands shot across the cavern, sticking to the spider's legs. The monster shrieked, stumbling as more webbing yanked it sideways.
Harry blinked, confused. "What—"
A voice echoed above them. Light, quick, joking even though the air smelled of death.
"Man, I really hate caves. Too much echo. Also, did someone order extra-large creepy crawler?"
A figure swung down on a line of web, landing on the rock with impossible balance. Red and blue suit, spider symbol on the chest, white eyes that shifted like they could squint.
Naruto's jaw dropped. "Whoa. Who's this guy?"
"Spider-Man," the figure said like it explained everything. He shot another web, sticking the spider's mandibles shut. "Friendly neighborhood, emphasis on friendly, though usually not in caverns with monster tarantulas, but hey, first time for everything."
Harry stared. "You're joking."
"Always," Spider-Man said.
The spider roared through the webbing, shaking free. Kakashi moved instantly, knife flashing. Naruto charged with a shout. Harry fired a Stupefy that cracked against the spider's side but only made it angrier.
Spider-Man flipped overhead, shooting webs faster than Harry could blink. "So, wizard kid with a wand, ninja guy, and—orange jumpsuit? Are we like… forming a band? Because I didn't bring my guitar."
Naruto grinned even while dodging a leg swipe. "You're funny. I like you!"
"Terrifying endorsement, thanks," Spidey muttered, sticking more webbing to the ceiling.
The spider lunged at Harry. He raised his wand but the dagger burned hotter, silver light bursting out on its own. The blast slammed into the spider's face, knocking it back into the cavern wall. Rock cracked, dust raining down.
Spider-Man whistled. "Okay, that wasn't web fluid. What's your deal?"
Harry panted, staring at the dagger. "Don't ask. I don't even know."
Before anyone could breathe, the cavern trembled. Another sound filled it—different, sharper, like thunder that didn't wait for the sky. A streak of red and gold flashed through, circling the spider so fast its legs tangled.
Then a figure skidded to a stop beside Harry. Red suit, lightning crackling, mask covering his face except for the mouth. He grinned, catching his breath.
"Sorry I'm late. Multiverse traffic is a nightmare."
Naruto gawked. "Another one??"
"The Flash," the man said, holding up a hand like introductions in a battlefield were normal. "Nice dagger. Looks dangerous."
Harry managed, "It is."
The spider thrashed, webbing snapping, rocks falling. Spider-Man jumped to a wall, Flash blurred to dodge. Kakashi didn't flinch, just pulled Naruto out of the way.
Harry pointed his wand again. "Confringo!" The blast hit one leg, cracking it. The spider screamed.
Spider-Man swung low, webbing both fangs, yelling, "Team effort, people!"
Flash zipped past, striking with a punch that cracked lightning. Naruto and his clones swarmed, stabbing kunai. Kakashi's knife slid deep into one of the joints. Harry's dagger pulsed one last time, silver energy bursting out like a bell.
The spider collapsed. Dead.
The cavern fell quiet again, except for dripping water and everyone's breathing.
Harry leaned against the wall, dizzy. "I… I can't keep doing this."
Spider-Man crouched next to him, tilting his head. "You look like you need therapy. And maybe a sandwich. Definitely sleep."
Flash smirked. "Welcome to the multiverse. Don't worry, you'll get used to it."
Harry laughed once, weak and sharp. "I don't want to get used to it."
The dagger hummed again, faint, like it disagreed.
Kakashi looked at the new arrivals. "You both came through the same… fracture?"
Flash shrugged. "Kinda. One second I was chasing some psycho through Central City, next thing I know, boom—cave with giant spider. Lucky day."
Spider-Man nodded. "Yeah, I was patrolling Queens. Blinked, ended up here. Not exactly the subway I was aiming for."
Naruto pointed at Harry. "It's him. The dagger. It keeps sucking people in."
Harry wanted to argue, but his scar throbbed. He closed his eyes, tired. "He's right."
Silence. Heavy. The cavern seemed to hold its breath.
Spider-Man finally said, "Well, mystery dagger, creepy forest, giant spider, multiverse meltdown… I've had worse Tuesdays."
Flash clapped Harry's shoulder, gentle but solid. "Looks like you're the key, kid. Which means—" he grinned, though his eyes were serious "—we stick with you."
Harry's stomach twisted. He looked at the dagger, still glowing faint in his grip. The whispers were there again, crawling under his skin.
"Open," they said.
The floor shook. Silver cracks split the cavern walls. Light spilled out.
Harry whispered, "Not again."
Too late. The world ripped open once more.