Gensokyo's first day in April began, as so many do, with screaming.

Of course, what this bodes for the rest of the day can vary widely depending on the tone, as long-time veterans have learned. For instance, cries of 'The horror!' meant that it would be mildly uncomfortable to go outside.

Screams of pain were usually answered by sending someone to get Eirin.

Ten or more screeching people meant that one should take another look at their house insurance plan.

For those few who could actually find insurance, of course. Most insurance companies treated Gensokyo in much the same way that arachnophobes treat two-foot tall spiders waiting outside their windows.

As such, Reimu was not surprised by the shriek that woke her. Unhappy, to be sure, but not surprised.

Incoherent nonsense that may or may not have been blasphemous pooled out of her mouth to soak her pillow... wait, no. That was the drool. But there were some murmured ramblings mixed in there!

After telling the morning what she thought about it, its mother, and mornings in general, Reimu forced herself to sit up and brain. That had been a shriek of disgust, which meant...

...

After a short period of time she came to the conclusion that she did not brain well without caffeine.

Standing in the kitchen, she tried to remember the steps of how to morning, but could not. She thought she had everything she needed, but what was she supposed to do with it?

Reimu hesitantly grabbed hold of a jar of leaves. After staring at it for an indeterminate period of time, she took a spoonful of the cured leaves and dumped them into a cup.

Huh. That didn't look like caffeine.

She dumped some beans into the cup after it. Nothing happened, which she assumed was a bad thing.

Truly perplexed, she sat down on the chair and tried to brain her way through the problem (which was very difficult, considering the circumstances). A light went off above her head as she realized what was wrong.

After she finished being overcome with shame, she poured creamer, sugar, creamer, honey and some creamer into the cup. The result looked like... uh...

Meh. It was close enough.

"Cheers," Reimu tried to word to no one in particular, although in her current state it sounded rather more like, "Jeeauhs," which sounded frankly awful. Then she poured the unholy concoction into her mouth and chewed.

And then she woke up like no one had ever awoken before.

Songs could be told of the intensity of her wakefulness and her hyperawareness of just about everything, if only anyone knew about it. Legends would be forged from her boundless energy, if only she could last the day without crashing.

But mostly, it gave her the presence of mind to consider that morning's waking scream. Which lead her to check the date. Which, in the logical course of events, lead her to panic.

It was April 1st. April Fools Day. The bitter thought made her shudder.

"Suika! I need-," she began, only to face-palm at her own stupidity. She sent her off on a sleepover at Alice's place for a reason, after all. She'd be planning to get her, too. She couldn't trust her.

She couldn't trust anyone.

April Fools Day made monsters even more monstrous. But she would not be taken unaware this year! Not Reimu Hakurei!

She began her careful inspection of the shrine to ensure that no one had set any traps or pranks up inside her home overnight. Each inch had to be double-checked for safety...

"Hey, Reimu! I'm going after Patchy with this great prank, but I need your help- woah!"

Marisa's with no doubt deceitful greeting was met with the blast of a danmaku.

"Out! Out out out out out!"

The nervous smile on Marisa's face was a far cry from her usual confidence. "Just hold on a moment, would you? Don't worry, I'm not going to-"

Reimu would not listen to this lying liar's lies. "No! I'm not falling for it this year... for once, I am going to have a perfectly enjoyable day today. So get out!"

"No seriously! I won't-"

Reimu did not permit the blonde to finish any sentences, which would no doubt be used to fool her into behaving like the fool everyone always made of her today. Well hah! Jokes on you, Marisa Kirisame!

That isn't exactly what was going through her mind when she threw the witch out of the shrine, slammed the door closed, and erected a barrier around her house.

But it was pretty close.

From all observations the UNSC had been able to make of the universe, astronomers have long ago come to the conclusion that the universe is shaped like an unimaginably massive fist with a single finger extended. The precise meaning of this is unknown, but it is unanimously agreed that it is supposed to be insulting somehow.

Because the universe is one sick bastard.

That's why Reimu studiously ignored the screams that sounded through the village on that most dreadful of days. Suika, Marisa, Cirno, Yukari... there was no shortage of pranksters dying to play tricks on others out there, and today was the time for them to let loose.

Understandably, this resulted in quite the ruckus as everyone found themselves soaked in cold water, got coated in flour, found frogs slipped under their hats, were playfully deceived or suffered the other tortures of the day.

This meant that when the sky ripped open above Gensokyou and ████ dragged itself from the tear in reality, Reimu paid the resulting screams no heed.

Terrified shrieks now echoed across the village as the entity extended its appendages to gift the puny mortals below it with its presence.

The first thing for anyone to do when encountering a horrific abomination is to run away; the best method of running away is to run towards someone who was probably strong enough to stop said abomination. This, of course, meant that Reimu was the one everyone turned to in their time of need.

"Reimu! Hey Reimu! Did you die in there or something?! We need you!" Marisa shouted as loudly as she could as she banged on the shrine's barrier.

"No! My shampoo and conditioner will be free of glue, dye and/or hair loss cream this time! I'm not opening this door!"

"Reimu, I don't like that any more than you do, believe me! But Gensokyo is under attack!" Alice yelled, standing next to Marisa.

Indeed, even as they tried to get Reimu to hear them over the roar of the crowd, the immense mass that was ████ was picking people out of the group with no seeming pattern.

"You'd like me to think that, wouldn't you? But then once I open the door to solve your 'attack', you sneak in here to put ants and honey in my bed sheets!"

████ extended itself like a great machine made of flesh, its gears and wires breaking off to engulf more bystanders. The screaming intensified.

"We need you out here, Reimu! I get that you've had problems before, but you have to trust us! Giant monsters are a lot worse than pranks!"

An angry huff came from inside the tree. "Hah! So you say, but today is the day you're actually supposed to lie to everyone! But my refrigerator is not going to be booby trapped with fireworks this year, and my deserts shall not be dosed with habañero powder!"

████ coated the earth in ██████████ formed from the bodies of ████ as it raised houses and trees into is five maws, crunching and devouring them with terrible teeth, each a fractal expanding in more directions than physics permitted.

"You know me, Reimu! I would never lie to you! Just come out. Please," Sanae begged.

The crimson flowed in innumerable rivulets as a circle that encompassed the whole of Gensokyo, thick tracks going straight through the village to form a rough star.

They heard the sound of footsteps on wood and the turning of tumblers in a lock.

"You promise?"

"'Yes, of course I do!"

An eardrum-shattering battle cry sounded over the ruins of Gensokyo as Tenshi, wrapped in crimson magic, descended from the sky to crash into ████, rocking the earth with the force of her blow.

"REIMU!"

Yukari Yakumo descended at a slower pace as danmaku streamed past her to slam into ████, which had come to give Gensokyo its blessing. Despite her distance, her voice bordered on the painful.

"THIS IS NO PRANK! WE NEED YOU! NOW!"

"You brought HER?! Why would you do that? She's the worst of all! I can't believe I almost fell for that. I didn't expect you to lie too, Sanae," came Reimu's panicking voice, accompanied by the distinct sound of a lock clicking into place.

Flailing heart-tentacles lashed through the streets as Suika and Yuugi unleashed heavy strikes upon ████'s flesh; but other than some slight movement, ████ gave no sign of being injured by their attacks. ████ rose from the ground in time to the movements of these extremities, the dance nauseating in its alien and visceral way.

"B-But this is serious! Even she wouldn't joke at a time like this!"

"That's what she said last year! And then she... she's the worst of all of them. The absolute worst," Reimu wailed as the sounds of screaming finally began to die off.

"When I got back to my shrine after the incident, my donation box was full with money. Money! I was so happy! But when took a closer look I saw that she... she...," Reimu broke off into tears. "She filled it with PLAY MONEY!"

...

...

"... Dear kamis..."

Reimu nodded along, not realizing that the exclamation was not, in fact, due to the commiserating with the terrible crime the gap youkai had committed against her.

Seeing the remaining gods shed their mortal bodies and ascend to their full divine power was not something anyone could watch in silence.

"OH COME ON! IT WAS JUST A HARMLESS PRANK!"

The surviving inhabitants of Gensokyo stopped. The gods stopped. ████ stopped.

Everyone stopped to stare at Yukari.

"IT WAS FOR YOUR OWN GOOD! YOU WERE OBSESSED WITH THAT STUPID BOX! I THOUGHT THAT WAS CLEAR ENOUGH, BUT APPARENTLY I WAS BEING IRRATIONAL!"

Reimu put up another barrier to block out the sound.

████ gargled in incomprehensible pain from Yukari's heartless, dirty trick, but strove on to give this world its gifts. The ████████████ that ████ had become sung for it and its victory.

Then ████ ate everyone.

...

...

...

Needless to say, once Reimu calmed down enough the next day, she had her work cut out for her.

- Chorus, New Repuplic Headquarters, March 31. -

"Hey, feeling better yet?"

"Urgh," Lieutenant Bitters groaned miserably, holding his stomach. He looked up at Palomo, who was carefully walking around the puddle on the ground.

"... Eating Captain Grif's old cream pie was a mistake," he dry-heaved, shuddering slightly.

"Yeah, I can see that..."

Both New Republic soldiers watched as the remains of the half-diggested pie of questionable age slowly crawled away, disappearing behind a crate.

"... Do you think we should be worried?"

"Nah, I'm sure things will be fine. *Burp*. Jesus..."

Additional Information

Human Village:

The Human Village is the place where most of Gensokyo's humans live. Even though some youkai are also visiting this place to shop, this is the safest place in all of Gensokyo to live. Humans from the Outside World that stumble into Gensokyo and decide to stay often have no choice but to live here as they would be unable to handle the youkai outside the village. The village itself has a powerful protector in Keine Kamishirasawa, who is capable of 'hiding' the history of the village's existence so that youkai cannot even reach the village, much less attack it.