Change is a Demon All its Own

Izuku had been feeling odd lately.

It had started with this odd little feeling in the back of his mind, something that pulsed a little when he passed certain people. It compelled him, told him that they were special.

A little anomaly that commanded his attention.

He would stare at them and instinctively track them with his fingers.

His mother would stop him and make him lower his hand, especially when the people became greatly uneasy. They would gulp and turn away, like young Izuku would snoop out something wrong in them if he maintained his attention.

About two weeks after this feeling in his head appeared, Izuku began to exhibit physical symptoms. His eyes darkened into black with red irises, causing his mother to rush him to the hospital, fearing he had begun bleeding into his eyes. Fortunately, it was a simple shift in melanin production: a harmless side effect among the many changes his body was undergoing.

Next, his appetite increased to twice that of a normal 3-year-old, coinciding with the emergence of a pot-belly. Oddly, the weight gain was solely in his stomach, the bump extra conspicuous against the backdrop of a thin frame.

The final symptom was a dull, throbbing pain that focused heavily in the tips of his right index and middle finger. The digits would pulse and throb and would even turn deep red if he used his hand too much. He tried to ignore it, but it grew harder every day.

The pain became sharp and piercing to the point that Izuku would swear something was actually going to poke through his fingertips.

Inko, in her understandable mother worry, took him to the hospital when she caught Izuku about to dig into his fingers with a knife to try to 'cut the pain out'. She had heard that quirks could alter the appearance of children and have side effects when they first aippeared, but this was too extreme.

This whole ordeal was starting to eat at her sanity and Izuku's social life. The eyes had already been deemed villainous by the crueler kids on the playground, some had claimed his new belly made him look pregnant, and the rest were concerned that his hand had a contagious infection.

She needed an answer or a solution now!

The doctor ran a battery of tests on Izuku to determine the root of the problem, whether this was caused by a quirk emerging or some sort of obscure illness. They took an x-ray of his fingers, and his toe to search for the joint, they did an ultrasound to check for masses in his slightly distended stomach, and they double checked his red eyes. Inko was sobbing in terror of what the doctors may find, fearing for her baby's health.

When the results came back, Inko nearly collapsed in relief that her son was not ill.

"It appears he's simply expressing a mutation quirk Mrs. Midoriya. While cases of children gaining a quirk completely different from that of their parents is very rare, it is far from impossible. The pain is most likely a side effect of the physiological changes. With no family history of a similar quirk, his body has no genetic predisposition to handle these alterations.

"Fortunately, the tests have revealed multiple aspects of his quirk: The eyes started out as simple discoloration, but they have now developed new receptors. Similar receptors have been found in the eyes of those with perception quirks, but the one's your son possess are very atypical and we can't tell what they are supposed to detect.

Now, the protrusion of his stomach is what's truly interesting. We've found the cause is a new structure forming within his abdominal cavity."

"What?!" Inko asked, distraught. Her eyes filled with tears once again.

"Don't worry, don't worry" The doctor reassured hastily, "the ultrasound revealed the mass to be very uniform and a biopsy revealed it to be non-cancerous. We have hypothesized that it is some sort of gland considering its composition and its connection to your son's fingers," the doctor explained.

"Which brings us to our next finding, we found out the cause of your son's pain. According to the x-ray your son's fingers are simultaneously deteriorating and restructuring. They appear to be both hollowing out and sharpening, into a sort of needle, for lack of a better term. They also have what I can only call 'tubes' connecting them to the mass in his stomach, leading us to believe they will spray or inject whatever this new gland secretes."

"What does this mean?" Inko asked worriedly

"Now, we cannot determine what the gland produces as we would need to acquire the 'finished product' if it were secreted properly, and we need to wait for his fingers and gland to finish developing," the doctor finished.

"So, what do we do for Izuku? He's been suffering so much lately because of his quirk appearing and I want to do what I can to help him," a watery-eyed Inko pleaded. The doctor simply gave her an understanding look.

"There is nothing that really can be done Ma'am, at most I can recommend you increase the portions of his meals to account for his increased appetite, but we can't really do anything about his eyes and pain medication could interfere with the proper development of his fingers. I ask you to bring him back for regular checkups, in case the gland grows to the point it compresses his stomach or the bones do not form properly," the doctor informed her.

They continued to converse about Izuku until the boy in question was brought into the room by a younger nurse.

Izuku looked up at the two of them, "My tongue and nose hurt," the boy announced as his nose began to bleed.

As it turns out, Izuku's quirk had begun to work on his other sensory organs. While his ears showed no sign of mutation, his tongue had doubled in length, the tip now covered in new receptors. The same with his nose, which grew slightly in prominence on his face.

None of these factors did any favors for Izuku's standing among his peers.

"He looks like a goblin!"

"I heard he's possessed by an Akaname! That's why his tongue got so long."

"I heard a Yurei went into his mouth and changed him. That's why his stomach got big!"

"I don't want to be possessed!"

Izuku tried not to let it bother him, and finished his sandwich in the corner of the room.

Izuku waited in the shade of a tree for his mother to pick him up. Fortunately for him, the other students were too fearful of his appearance to directly bully him. So they just left him alone, isolated among the crowd.

"I'm alone again,

"Oh I am alone again,

"Sitting under a tree I have no friends," The lonely boy sang to himself as he tapped a tune on a nearby log.

"Huh, what's this?" The black-eyed boy leaned over the log to get a closer look. *poke* "Ew, it's all slimy,"

The orange net thing on the log entranced the boy despite its grossness. It shined and he swore it shivered slightly under his gaze. It had a scent to it that Izuku could not describe, and he fought the urge to taste it.

Before Izuku knew it, he was reaching forward with his right hand, the fingertips burning worse then they ever had before.

They started to bleed- "Izuku, mommy is here!"

"Mommy mommy mommy!"

Without much thought, the preschooler took out an empty jar from his pocket and stuffed the patch of bark with the slimy thing inside. Closing the lid he stuffed the jar into his backpack and ran towards his mother, to be enveloped in a hug.

"I will call you Mio!" Izuku declared to the Pretzel Slime Mold he had found earlier today. He had shown it to his mother, who, while hesitant, allowed her son to keep the tiny slime mold. After looking up the origin of the odd little lifeform, they set it up in a little fish bowl with some shredded vegetable matter left over from dinner preparation.

The slime mold shivered once again, seemingly in response to being named. Izuku couldn't help himself, and reached for the blob with his right hand once again. Unlike at school, his fingers made contact.

"OW!"

With a noise somewhere between ripping fabric and stabbing meat, two pin-pricks shot out of Izuku's fingertips and into Mio. An odd payload squirted into the gestalt organism. It was black and seemed to swim throughout Mio, dispersing quickly in the time it took Izuku to shake the pain out of his hand.

Checking his fingers, Izuku failed to the see the new protrusions due to their miniscule size.

"Izuku, its time for bed sweetie." Inko said, entering the living room. "It will still be here in the morning, but big boys going through big changes need their sleep."

"Okie Doke! Bye Mio!"Izuku said as he ran to his bed for his mother to tuck him in.

Unbeknownst to either, Mio began to develop black spots.

Izuku's odd red eyes stared into a pair of glowing white dots. The dots blinked twice back at him.

Mio had changed considerably over the course of the night. His body had grown and rounded out into a thin circle. The many holes spread throughout his body had shrunken down to pinholes. He looked like a perforated coaster.

Sitting above the bright glowing dots that Izuku was sure were eyes, was a small black antennae. It bobbed and swayed in a nonexistent breeze.

...

*poke*

Izuku booped the dangling thing.

It stretched a tiny bit and booped his finger in turn.

"Mom! Mio changed!" Izuku called over his shoulder. "A lot!"

AN: This idea has been slow cooking for months.

As always, please leave feedback, and if anyone draws fanart, I would love to see it.