Shwoof

Marisa Kirasame forcibly slid open the doors to the Hakurei Shrine.

"Oi, Reimu!" She called out, striding in without any regards to silly things like 'politeness' or 'noise control'.

Reimu Hakurei, who was already up and sitting at the kotatsu in the main room, leveled a flat stare at the intruder.

"I'm right here , Marisa."

The witch's grin widened a bit as she finally spotted the shrine maiden sitting directly in front of her. A softball sized yin-yang orb softly rolled on top of the table, being nudged by its surly owner's hands.

"Well well well." Marisa said, delicately removing her giant black boots and subsequently tramping over to an empty seat. "Ponderin' our orbs over here, huh?"

Reimu decided to stay silent. It was way too early to attempt to deal with the blonde force of nature. Let her say what she has to say so she can leave.

"Anyway, guess what day it is!" Marisa continued on, fishing for an answer immediately after the decision to not say anything was made. "Go on, guess!"

Reimu sighs. "Is it another outsider holiday that you heard about from that psychic and subsequently put through fifty mental and social filters to come up with a holiday that, while it technically meets the criteria, is wrong in a number of fundamental ways to great comedic effect for anyone that knows what the day is supposed to be about?"

The witch's grin becomes lopsided. "Jeez Reimu, you didn't have to call out so many burgeoning authors like that…"

Then, her smile comes back to its former glory. "Anyway- you're close! But, I think I got the spirit of this one just right! Hold on…"

Marisa begins digging through her poofy skirt, eventually finding a polished wooden cylinder. She sets it on top of the kotatsu, next to the rolling yin-yang orb, before continuing her speech. "So, this one's pretty simple. On this day, everyone gives someone else a small canister of snacks! That's it. No worrying about what someone needs, or spending a lot of money, it's just a nice day to enjoy some food." Her grin turns into a genuine smile. "So I thought, hey, why not spend it with my best bud!"

Reimu's eyes widened a bit, a small blush appearing on her face. "O-oh. Yeah, that- that doesn't sound too bad…" She says, reaching across the table for the can. Lifting it up, the shrine maiden can tell that the word 'peanuts' is carved into the wood.

"It would certainly make up for all the一"

Bwooosh

The moment Reimu opened up the can, a thick plume of bright yellow smoke burst free, instantly filling up the shrine and making it impossible to see for a brief period.

The shrine maiden coughed a bit as the brightly colored gas was cycled out for fresh air, her eyes closed to protect them from the smog.

"Marisa!" She managed to sputter out. What kind of tomfoolery was happening now?

"Heheheheheheh!" The probable culprit laughed. "April fools, Reimu!"

"W-what?" Reimu blinked her eyes open, confused. Ironically, this only served to make her even more baffled.

The entire Hakurei Shrine was palette swapped. As the brunette looked around with wide eyes, she could plainly see that every inch of her home was some shade of yellow. The flooring, the sliding doors, the yin-yang orb. In shock, she looked down, and yep. She was now the Yellow-White miko instead of the Red-White.

Even the ground's color was yellow! (Laugh. Now.)

Marisa, meanwhile, was practically rolling on the floor with laughter.

"Hahahaha! You should totally see your face right now!" She wiped a tear from her eye. "April first isn't a day for sharing snacks with each other; what kind of lame holiday is that? It's a day for playing pranks and mirth!"

Lost as she was within her own mirth, the witch failed to notice Reimu stand up ominously.

"This is funny to you, then?"

"Absolutely! You look like a lemon!"

"Well, I'm about to be real hilarious then."

"H-huh?"

It was at this moment that Marisa realized how much danger she was in.

" ｢Dream Land｣-"

"W-wait, Reimu! It's reversible, I promise!"

"-Super Duplex Barrier!"

Meanwhile, in a classroom in Japan, a certain brown-haired student snaps out of her semi-dozing state. Visions of a comically large amount of danmaku blocking out the skies of a hidden paradise, and her hand covered in shaving cream fill her mind.

"Y'know, maybe I shouldn't try and visit today…" she murmurs to herself.