"Mr. Aizawa, it would be unwise for you to go down there." Izuku says, grabbing his teacher's arm before he could engage the villains.
"Midoriya, you can't be a hero with only one trick." Aizawa replies.
"That's not what I mean, tactically it would be better for you to stay within sight of us students until we leave the building." Izuku explains.
"And let them catch us as we retreat, it would be better to distract them here." Aizawa argues, moving to remove Izuku's hand.
"Then let me be rear guard, or more accurately my quirk." Izuku says, "I explained earlier that I have considerable reserves and a method of transport. Let me show you what power I hold, release the endless wave that I have prepared!"
"Your idea has merit." Aizawa ponders.
"I'll also send some to call for help." Izuku pushes.
"Alright, unleash your swarm." Aizawa says, "everyone, stay together and head for the door!"
"My pleasure." Izuku says, positively bubbling with anticipation as he sends the command.
"I can't let you escape." Kurogiri says, warping in front of the students, "Allow me to introduce us, we are the League of Villains and..."
The villain stops his monologue as he feels a faint rumbling in the earth soon even the less aware students feel the growing vibrations beneath their feet.
"What is that?" Thirteen asks.
"They're coming." Izuku answers cryptically.
"Coming? There is no help incoming child." Kurogiri states.
"Something big is approaching, more than one something." Jiro says, jacks in the ground.
"Indeed, I don't know what though." Shoji confirms.
As the shaking hit a crescendo the ground not far from the students began breaking up and unknown to them the same deformation was occurring at several other locations throughout the USJ.
"Stand back!" Momo commands, stopping the curious Kirishima and Kaminari from investigating the disturbance.
"An earth quirk?" Kurogiri questions, "your acting is convincing but it's not enough to fool me. I've had enough of this."
Kurogiri moves forward to warp the students but is stopped by Aizawa, before he could regain his bearings the deformed earth erupted as a massive worm broke the surface and nearly reached the ceiling, unleashing a ear splitting screech as it settled and opened its mouth wide, unleashing a horde of insectoid monstrosities.
"I think I'm going to leave you to it." Kurogiri says, fleeing to the central plaza.
Soon similar screeches were heard around the USJ, the swarm had arrived.
It all started over ten years ago in an unassuming park.
"Stop hurting him Katchan!" A young green hair boy shouts as he stands between a group of bullies and a purple haired child lying on the ground.
"Move Deku, this one needs to learn his place, the strong are on top and everyone else listens." A blond bully commands.
"I won't move, Heroes use their quirks to help people not get others lunch money!" The green haired boy replies.
"And a Deku like you is going to be a hero?" The blonde laughs, the other bullies joining him.
Noticing the green haired boy wasn't moving anytime soon the blond moves forward and punches him in the stomach. The green haired boy bends over from the blow and vomits a wave of purple something that covers the ground in front of him, and an unknown creature emerges from the goo.
"What the hell?" The blond yells, frantically wiping the stuff off himself while retreating.
"Is this his quirk?" A lackey asks.
The green haired boy walks forward and picks up the front of the unknown creature, a maggot like carapace covered worm it attempted to cuddle into the boy as he held it.
"It looks like a disgusting but useless quirk." The blond says, "I'm out of here, I don't want this crap on me any longer."
The blond's lackeys agree and leave the park.
"Thank you for helping me." the purple haired child says.
"It's what any hero would do." the green haired child replies.
"You've got a powerful quirk."
"I don't know yet, this was my first time using it."
"Well, I've got to go, Thanks again." The purple haired child says.
"Bye." the green haired child says, before walking off to find his mother and tell her about his quirk.
"That's a very nice quirk Izuku." Inko says, worrying about how such a quirk would be seen by others.
"Yeah, mom isn't it cute?" Izuku says, holding the insectoid he had regurgitated earlier.
"It sure is." Inko says, noticing how it seemed to cuddle izuku like a pet would. "Does it do anything?"
"I don't know." Izuku says.
Evolve, evolve, evolve.
Jumping at the sudden voice in his head, Izuku stares at his insectoid pet and thinks about it evolving.
The creature suddenly inflates and forms a bubble like form on the ground.
"Oh, that's neat," Inko says. "What's it doing?"
"Evolving." Izuku says.
In a few seconds the bubble bursts and a similar creature burst from within. Stretching over two meters in length with a large triangular wing and a pair of pincers hanging below its hovering form.
"Oh my, it's quite big now." Inko says, "can it get bigger?"
"I don't know, maybe he knows?" Izuku answers.
The creature nods.
"How big?" Inko asks, wondering if it would fit in the apartment.
The creature proceeds to float across the entire entrance of the park around a hundred meters.
"Let's keep it at this size for now." Inko says, "I'll talk to your school about giving you a week off and we'll go to the countryside."
"Yay!" Izuku cheered and went to play with the creature, who seemed to be less cuddly than before it evolved.
"Alright Izuku, your grandparents owned all this land, but since they died I've been renting the arable land to the neighbors, this forest though should be quite private, let's practice your quirk!" Inko says as she and her son finished setting up a tent in a large clearing.
"Alright mom!" Izuku says, then tried to remember the feeling of vomiting earlier.
"Why don't you let Creature evolve again while you practice?" Inko says settling down on a lawn chair with a good book while thinking about her son's lack of naming talent. 'If he tries to name his first born 'Child' I'll have a heart attack.'
"Alright, Creature, evolve again." Izuku says.
Creature moves away from the pair and settles into the ground expanding rapidly into a familiar bubble-like form easily dwarfing the pair as it grows to the size of a small house and beyond.
"Well, good thing we didn't do this at the park." Inko says, fascinated by the rapid growth.
Meanwhile Izuku was focused on activating his quirk again.
'I don't think pain could be a trigger, that wouldn't make sense.' Izuku thinks, 'how about a sucking sensation? No...'
Izuku continued going through a series of feelings but didn't make any progress, his mother noticed this and invited him to take a break and watch Creature grow.
"Don't worry Izuku, it took me weeks to figure out how to pull things to me." Inko says.
"How do you do it?" Izuku asks
"Well, I imagine a floating hand and I pull it in like it's on a rope." Inko explains.
"You imagine a hand?" Izuku asks.
"Yes, it's a magic hand that I control with my mind." Inko says.
"Maybe I should imagine what I want instead of trying to feel something?" Izuku asks.
"You should try whatever feels right." Inko says.
"Ok mom, I'll try that." Izuku says.
"But first, we eat!" Inko says pulling out a cooler and a camp stove.
"But mom, I want to try my quirk now." Izuku wines.
"No buts, you can't think properly on an empty stomach." Inko says.
The next morning Izuku woke early to try his quirk again, but as he snuck out of the tent he saw a massive fleshy structure pulsating in front of him.
"Mom! Wake up! Creature finished his evolving!" Izuku shouts.
"That's wonderful dear, give mommy five more minutes." Inko replies automatically.
"There's more creatures!" Izuku observes.
"What?" Inko shouts, instantly awake.
Leaving the tent Inko stares at the massive living building growing before her, her bare feet notice the purple substance had returned and was covering the ground all around the clearing and that three more of the original creatures were rolling around at the base of the structure.
"Were going to have to think of a name for them, Izuku." Inko says, worrying about how many would eventually appear.
"Larva." Izuku says, "Creature says they are called Larva."
"Can Creature tell you more about himself." Inko asks. "And about his species?"
"He can't speak properly, but he keeps repeating Zerg and numberless." Izuku answers.
"Oh dear." Inko says.