Work Text:
When summer vacation arrived, Marshmallow and over a hundred lively mandragoras accompanied Haruaki back to his hometown in Osaka. The Abe household buzzed with more energy than ever, its rooms now overrun with the tiny white plant creatures. Amaaki, pale-faced, refused to venture anywhere near those Yokai he despised.
Adding to the chaos, another unexpected guest joined the household—Sano Mikoto, the Yakubyougami, who reluctantly spent his summer break at his homeroom teacher’s home. The young boy, however, didn’t complain openly about being dragged along by Haruaki, preferring to bottle up his irritation for a private venting session later. He’d mutter about how the principal could’ve at least told him before about spending his summer vacation with this guy.
Despite his initial reluctance, Sano didn’t entirely hate staying at the Abe household. Haruaki’s parents welcomed him warmly, while Amaaki, well, he was just like usual. On the bright side, Haruaki himself—acting like a personal tutor—helped Sano with his homework. It would have been great if Haruaki didn’t also annoy him too much.
Sometimes, Marshmallow would sit by and watch Sano tackle his homework. While some assignments seemed too complicated to understand, others, like the art diary project, sparked interest. Sano’s drawing was amazing—one of Seimei-kun was so cute and idiotic that it mirrored the real-life counterpart perfectly. Marshmallow was so impressed that he begged Sano to teach him how to draw.
When Haruaki saw the drawing, he showered Marshmallow with affection, praising them with enthusiasm bordering on excessive: "Adorable! Absolutely brilliant! My Marshmallow is a genius!"
Haruaki even planned to frame the artwork, behaving like a doting father bragging about his child’s first masterpiece. Sano, watching them blankly, mumbled something like, “What is he? An idiot doting father?”
Once Marshmallow’s artistic appetite was satisfied, he discovered another intriguing and exciting homework project— an independent research project .
One day, Marshmallow noticed Sano working on this particular assignment mid-vacation. The yakubyougami was looking at his homeroom teacher watering the other plant yokai while humming a cheerful tune, his long cowlick swaying rhythmically. Intrigued, Marshmallow tugged on Sano’s sleeve and asked,
“Sano-kun, what are you working on?”
“Independent research,” Sano replied.
“Independent research? What’s that?”
“It’s a homework project where you can research anything you’re interested in.”
That sounded complicated. Marshmallow tried to peer into Sano’s notebook, only to find it filled with many difficult kanji. It might be easier to ask Sano-kun, Marshmallow thought, asking, “What’s your research about?”
“A rare animal,” Sano said with a shrug.
“Rare animal?”
“Yeah, the one with antenna hair and has a sailor uniform fetish.”
“Huh? All we have here are mandragoras and Seimei-kun though?”
Sano didn’t reply, leaving Marshmallow puzzled. Perhaps this rare animal was invisible to mandragoras? Regardless, remembering Seimei-kun’s advice about not disturbing people while they worked, Marshmallow decided to leave Sano in peace.
Instead, Marshmallow had his own plan—he wanted to conduct their own independent research project!
Running over to Haruaki, whom he affectionately called Seimei-kun, Marshmallow climbed onto his shoulder and whispered, “Seimei-kun, Marshmallow wants to do an independent research project too! Can Marshmallow borrow some paper and a pencil?”
“Of course!” Haruaki replied with a bright smile. He always doted on Marshmallow. The little one gleefully ran off with the paper and pencil he wanted, Sitting next to Sano, excitedly declaring, “I’m going to research humans! I’ll study Seimei-kun!”
Sano froze. He suddenly turned his head so fast to the little plant yokai, looking at Marshmallow in disbelief.
“What’s wrong, Sano-kun?”
“…Nothing. Good luck with that,” he replied, looking oddly concerned but not elaborating further. Marshmallow didn’t understand why, but that might not be necessary, he thought.
And so began Marshmallow’s grand mission: observing Seimei-kun!
Marshmallow’s Observation Journal: Seimei-kun
August 12th
Today was my first day of research! Seimei-kun visited Beniko-chan and Hijitan-kun’s house. Everyone was having fun doing homework together, but then a journalist showed up because of some rumors about yokai sightings at a B&B something. (Marshmallow didn’t remember the name, oops!)
Seimei-kun pretended to be a dead body because he was one of the funny-faced trio. But then he got spotted after! He panicked, so he crawled away in a wheel pose while laughing! It was so scary that even Ogoso-kun and Fuji-kun screamed. Marshmallow nearly had a heart attack!
So humans can crawl in wheel pose at high speeds when scared? Humans are so terrifying!
August 15th
Day three of my research. Today, Seimei-kun stayed home all day with Sano-kun. When Seimei-kun wandered into Sano-kun’s room, Sano-kun gave him a German suplex.
Then, a G (you know, the flying brown thing we don’t name) flew into the room. Sano-kun screamed and told Seimei-kun to deal with it, but Seimei-kun was scared too. He yelled, “No waaay!”
But when the G flew closer, Seimei-kun’s cowlick turned into a hand, grabbed the G, and flung it out the window. Amazing!
So humans can use their hair to grab things? Incredible!
August 20th
Today Marshmallow learned that Seimei-kun wakes up and goes to bed at the exact same time every day. No matter what, he’s fast asleep when it’s bedtime.
So humans can set themselves on a schedule like robots? Marshmallow haven’t heard that before!
August 22nd
Seimei-kun went to the convenience store but got shaken down by middle schoolers. He panicked and ran all the way home in two minutes! The store is definitely over a kilometer away!
So when humans are scared, they run faster than a kamaitachi. Amazing!
August 27th
Summer vacation is almost over. Seimei-kun looked so sad about it that he liquified onto the floor like slime.
So Humans can turn into slime when they’re too hot or unhappy? How can they do that?
When school resumed, Haruaki went back to Hyakki Academy. A lot of homework was waiting to be graded on the teachers’ tables. The only Human in Yokai school went for his class, only Miki and Hatanaka were in the faculty room. Marshmallow ran to those two who were Haruaki’s best friends.
“Rintarou, Glasses, look at this!”, The little one called, “Marshmallow did an independent research project too!”
“Hm? What did you research?”, Miki asked.
“Wait, why did you call him Rintarou while you called me glasses?”
Hatanaka frowned, but was totally ignored as Marshmallow wanted to show off his independent research. He showed it to Rintarou, saying so proudly.
“I’ve researched a human, Seimei-kun!”
As Marshmallow said, those two gave him a concerning smile.
Well, Haruaki really was a human, but his behaviors were…um…not so human, if they were to say. They didn’t think their friend was suitable to be researched as a human. Surely, this report must be filled with something that looked more like a new type of yokai.
Those two teachers, who read through the journal, were baffled.
Yup…nothing in this report looked like a human! How should they react!?
His friend had strayed too far from humans, Rintarou sighed. “Marshmallow, next time, maybe observe someone who’s… a normal human, okay?”
“Eh? But Seimei-kun is human, right?”
“Don’t lump him in with humans, that guy is more yokai than yokai.”
Hatanaka said. Marshmallow tilted his head a little in confusion. What’s wrong with his Seimei-kun observation report? Marshmallow didn’t understand at all!