(TEASER) SAVING EARTH BET, ONE PUNCH AT A TIME: A ONE PUNCH MAN/WORM CROSSOVER FANFICTION

It was a normal day.

The sun was shining, the air smelled faintly of concrete dust, and Saitama was walking home from his favorite supermarket with a plastic bag dangling from one hand. He was already thinking about dinner. Maybe he would have a hotpot, or omelet rice again. Maybe just instant noodles with eggs.

Either way, a simple dish was the order of the day. 

But when he turned the corner, the world abruptly changed.

The bright sky dimmed as if someone had pulled a curtain across it, thunder rumbled overhead, and heavy storm clouds rolled in far faster than was natural. The buildings around him looked wrong too, still dilapidated and abandoned like the Ghost Town of City Z, but their damage seemed somewhat… older. 

Saitama blinked, more annoyed than alarmed. His plastic bag rustled as the first cold drops of rain splattered against his bald head.

“…Weird,” he muttered, scratching his cheek.

Then the shouting started.

A tide of people rushed past him, soaked in the sudden downpour, eyes wide with panic. Men and women shoved each other aside, children cried as they were dragged along, and the street became a chaotic blur of fear and noise. Saitama stopped walking, caught in the throng for a moment, his brows knitting together.

“Huh? People? That’s new,” he said aloud. He was used to silence. After all, his apartment was in the Ghost Town, where no one but him and Genos lived. The idea of a stampede in the area felt wrong.

Still, he shrugged and resumed walking, the bag swinging lightly at his side. It was probably some monster attack again. Genos would have lost his mind over it—charging into battle, and shouting something inane—but Saitama just wanted to get home before his grocery was destroyed.

Except… when he reached his street, it wasn’t his street.

Where his building should have been stood nothing but another ruined husk, windows shattered, and walls darkened by old water stains. 

Now properly irritated, he hopped onto the nearest rooftop with an easy crouch and scanned the horizon. In the distance, something massive moved between buildings, each step shaking the earth slightly. Sparks of light danced around it, though he quickly came to realize that they were figures, and the lights were flashy powers. Heroes, locked in combat.

Guess they’ll know what’s up. 

One jump carried him across the city blocks, air whistling past his ears. He landed softly on a rooftop near the battle, watching for a moment. The monster loomed, a hulking shape of scales and claws, moving ferociously in the storm. The ‘heroes’ fighting it weren’t the Association types he recognized, though admittedly, Genos had a better head for that sort of thing. Maybe he should look for Genos. The teen should be around here somewhere. 

Saitama cocked his head to the side.

But before he could do anything, someone in a suit of silver power armor came charging toward him.

“Metal Knight?” Saitama asked, squinting.

The armored hero didn’t make it to him. The monster swiped a claw the size of a truck at him, and without thinking, Saitama blurred forward. In an instant, he’d plucked the hero out of danger and set him down gently on a rooftop a block away.

“Huh?” came a startled voice from inside the armor. A teenager’s voice.

Saitama frowned. Weird. I thought Metal Knight was older…

He shook his head. It didn't matter. The monster was the priority. If he wanted directions back to his apartment—or at least, directions to somewhere he knew—he needed these guys alive.

“I’ll be back,” he told the hero.

Then he launched himself at the creature.

The monster saw him coming and swung again, sharp claws slicing through the rain. Saitama didn’t bother dodging. He simply pulled his arm back and aimed for the limb, only for the beast to try to dodge at the last moment, forcing his punch to graze its limb instead.

The result was still the same.

The limb vanished in a thunderclap of force, torn away along with a whole line of ruined buildings behind it. Concrete and steel shredded like paper, pulverized along with the street below.

The monster howled, flesh bubbling as the ruined stump regenerated in seconds. It retaliated with a swipe, claws sparking uselessly against Saitama’s skin as he rotated with the force. Then came a surge of water, an entire wave conjured from nowhere, drenching him from head to toe.

“Aw, man,” Saitama muttered, shaking his arms. “Now my groceries are soaked.”

The beast froze before turning to run.

Saitama’s expression flattened.

One jump carried him overhead. He brought his fist down like a hammer, the punch connecting squarely this time. The monster’s head was obliterated in an instant, its body collapsing with an earthshaking crash.

From the space its head was rolled a strange orb, pulsing slightly with light. Even as he watched, tendrils of flesh sprouted from it, groping outward to rebuild the fallen body.

Saitama sighed, stepped forward, and crushed it beneath his heel. The ground crumpled in a wide crater.

Silence followed, broken only by the patter of rain.

When he turned back, the heroes had drawn closer. They kept their distance, wary, as if unsure whether to thank him or attack him. But at their head was a man in a skintight blue-green suit with a hood and cape. His stance was rigid, his eyes sharp behind the glass helm as he called out across the storm:

“Who are you?”

Saitama cocked his head. They didn’t recognize him. Maybe his popularity hadn’t spread this far, or maybe it was the lack of costume. Either way, his answer didn’t change.

“My name’s Saitama,” he said simply. “I’m just a guy who’s a hero for fun.” 

The heroes stared, and the rain kept falling.