Worst Nightmare

by chibikaty

Dr. Garaki conducts an experiment to swap Tomura and All for One's bodies. The device will lock onto anyone sharing All for One's DNA. But that won't be a problem, because All for One has no living relatives…right?

Title: Worst Nightmare

Summary: Dr. Garaki conducts an experiment to swap Tomura and All for One's bodies. The device will lock onto anyone sharing All for One's DNA. But that won't be a problem, because All for One has no living relatives…right?

Author's Note: Thank you to Shad0whuntress for this cool idea. Since I bullied Dabi with a bodyswap, I did the same to Tomura. They would both insist the other must suffer an equal amount.

#

Tomura frowned as Dr. Garaki strapped his wrists to the medical chair. "What the hell are you doing?"

"You might twitch during the procedure," the doctor said. "It's only a precaution. You could always decay the restraints, what are you worried about?"

"I'm not worried." Tomura scowled. "Just get this over with. You promised me that this stupid procedure will level me up."

"You'll soon become a worthy leader." Garaki threw a switch. "Because the only worthy leader is All for One!"

"Huh?" Tomura didn't even have time for a curse before electricity arced over his body. He twitched, then his head slumped over.

"Master? How do you feel? Is that you in there, All for One?" Garaki peered out from behind his desk.

Izuku Midoriya, inside Tomura's body, gulped and said, "Yes, I am definitely All for One. Can you get these straps off me?"

"Can't you decay them, master?"

"Decay…so that's who I…right." Izuku used a little too much power and dusted half the chair. Taking a deep breath, he visibly pulled himself together. Then he pasted on a fake smile. Standing up, he asked, "Why don't you tell me all how our plans are going? I'm old and forgetful. Refresh my memory."

#

Tomura opened his eyes to see his own personal living hell.

All Might's stupid smiling face spread across every single inch of this space. The bedcovers had an All Might pattern. The headboard had a pair of yellow hair tufts. For some insane reason, as if that wasn't enough All Might, the pillows were red, blue, and yellow with a stuffed bear wearing All Might's costume resting on top. The rug, the dresser, the desk—every last bit themed after the number one hero. The watch on the nightstand had an All Might design. He had infested the curtains and the window decals. Worse of all, an entire army of All Might figurines and posters covered the walls. There must be at least a thousand All Mights, each with the same brilliant grin.

"AHHHHHHHHHHHHHHH!" Tomura wailed in despair and tried to decay the bed.

Nothing happened. His power was gone. This was a true nightmare!

Screaming like a maniac, Tomura ran around the room ripping down the posters. He shoved all the figurines into the closet. He stuffed the covers and pillow under the bed. Then he ripped Bear Might's arms and legs off.

Yet no matter how Tomura tried, he couldn't wrench loose the carpet. Looking down at his legs, to his horror, he saw that he wore All Might pajamas!

Shrieking and hopping, Tomura ripped his clothing off. He ransacked the dresser. Nearly every article of clothing had All Might's face and colors. He was finally forced to settle for jeans and an ugly white T-shirt with the word "T-shirt" written in English on the front.

Collapsing to his knees, Tomura panted. He'd experienced nightmares of his entire family dying, but this…this was an entirely new level of horror. What sort of freaky chemicals did that creepy doctor fry his brain with? Or could he have died and gone to the bad place? Despite all of Tomura's crimes, surely he didn't deserve such a horrific punishment.

An All Might decal, loosened by his rampage, peeled off the window and fell on his head.

"AHHHHHHHHHHHHHHH!" Tomura ripped it to pieces. He accidentally ripped out a few strands of green hair. Green hair?

This place was a nest of All Might worship. It had to be burned clean. His quirk still wasn't working. Tomura staggered out of the room, seeking matches.

As Tomura passed the bathroom, he considered if water would work to ruin the posters, but decided it wouldn't destroy them thoroughly enough. He glimpsed his reflection in the door mirror. It took him a few seconds to understand why the wild-eyed hero brat in the mirror moved when he raised his fist to punch the image.

Somehow, he'd turned into Izuku Midoriya. This really was the weirdest dream ever. Maybe his subconscious was working out some issues related to the All Might worshipping brat? But since when had Tomura even cared about Izuku that much?

Tomura punched, trying to activate the hero brat's quirk. Nothing happened. He had the peculiar sense that the power had been denied to him, as if it lay behind a thick wall. This stupid dream couldn't let him get even one decent stat?

Fumbling around, Tomura made it to the kitchen. He opened drawers randomly, looking for a box of matches. The fridge had a dozen All Might magnets, which went straight into the trash.

Behind him, All for One asked, "Are you hungry, ducky?"

Tomura whirled around. All for One stood in the doorway wearing a bathrobe and Darth Vader slippers. Stifling a yawn behind his hand, All for One said, "Inko left early in the morning for the downtown Saturday flea market. She said there are toaster waffles for breakfast in the freezer."

"Sen—?" Tomura's aborted attempt to call his sensei's name cut off as All for One hugged him.

Tomura had never been fond of physical contact, which had worked out because his adopted guardian had never been huggy. What on earth was this? Tomura cursed and struggled.

"Language, ducky." All for One mussed his hair.

"This is the weirdest dream ever," Tomura said.

All for One laughed. "Yes, it must be a dream come true to have your father return from America."

While Tomura was stunned and confused, All for One put the waffles in the toaster. What could this dream mean? Did Tomura secretly long for more warmth and hugs from his guardian? No, he felt very certain he didn't. Maybe this was a new form of hell? How had his subconsciousness come up with his sensei having an All Might fanboy for a son?

Robotically, Tomura sat down at the table. All for One cut up the pancakes, then held out a bit on his fork. "Open up, here comes the airplane."

Tomura glared. "I'm not letting you feed me. Umph!" He choked as the waffle went into his mouth, then spat it out. "Stop that!"

"You'll never be too old for me to feed, ducky," All for One said.

"I'm not a child or a waterfowl! I'm in my twenties."

All for One blinked. "I know I was gone from home for a long time, but that can't be right."

Tomura crossed his arms. "I'm not hungry. I need some matches to burn the All Might merchandise."

All for One's entire face lit up. "You're finally gotten over your hero-worshipping phase? I knew someday the false heroes would disappoint you. This requires celebration." He tried to hug Tomura again.

"Nope." Tomura fended off the hug with both hands. "Sweet PlayStation, you are such a weirdo. I don't know why I dreamed up a version of you like this. I'm not Izuku Midoriya, I'm Tomura."

All for One stopped. His eyes narrowed. "You have been acting odd."

Tomura rolled his eyes. "What kind of father takes so long to notice?"

"It would be too much to hope for you to give up your beloved collection."

"Are we burning the All Might merch or not?"

"You stole my son's body!" All for One lunged, arms swelling up. "Are you so jealous of my affection for Izuku?"

Tomura ducked. "Are you kidding me? No sane person would want your creepy affection!" His sensei did not seem to be listening. A dark aura radiated off him, as his body sprouted with dozens of quirks.

And Tomura still couldn't use his borrowed body's quirk. He gulped and ran.

Dodging a spout of flame, Tomura reached the front door moments before All for One. The heat convinced him that this was not a dream. Somehow, he'd swapped bodies with a hero student. And he might be about to die. He ran outside—and ran smack into All Might.

Beaming, the number one hero crowed, "I'm here to pick you up for breakfast. We were going to Denny's, remember?"

It was a measure of Tomura's desperation that he actually hid behind All Might.

The inside of the house became eerily silent. Clearly All for One didn't want All Might to see him.

"Let's go," Tomura said, glancing over his shoulder.

Even All Might was better than the nightmare of a father he'd left behind.

#

Izuku escaped from Dr. Garaki's evil laboratory after memorizing the location and a massive information dump on All for One's plans. His teachers would love to hear this. The trick would be how to approach them without them arresting him, as he still had Tomura's borrowed body.

And he needed to find a way to swap them back. Izuku refused to live for the rest of his life as a crusty NEET. Even more importantly, he refused to give up One for All, his favorite piece of hero merchandise.

Izuku went straight home first. He needed to ensure Tomura wouldn't do anything bad with his body. Fortunately, his mother was away that morning. His father was supposed to come home, but Izuku didn't have any real faith in that happening because his father always had work emergencies.

There was a spare key under the doormat. Hisashi had left a note on the fridge for Inko, saying that he'd gone looking for their son. At least that meant his father was safe, but now Izuku had to worry about Tomura wandering around with his body. Izuku went upstairs, hoping Tomura had left behind his phone so he could get help from his teachers.

A scene of unimaginable carnage greeted his eyes. His beloved posters had been ripped and shredded. Every All Might face in the room had been marred. Bear Might, the treasure of Izuku's childhood, lay on the floor with stuffing pouring out of the severed arms and legs.

Tears flooded out of Izuku's eyes. He picked up his beloved Bear Might and cradled it to his chest. All other goals and plans left his mind as he screamed, "TOMURA SHIGARAKI MUST DIE!"

#

"What a beautiful day," All Might said brightly.

"Do you shout everything you say?" Tomura grumbled under his breath. "Is your volume setting broken?"

"My boy, would you like to catch a movie after breakfast?"

In the name of video games, what was this madness? It had been bad enough to have All for One acting so strangely. Now All Might was acting all fatherly too? This continued to be Tomura's worst day ever.

The blue stare meant a reply must be expected. Tomura muttered, "I'm going to be busy playing video games all day."

Somehow, impossibly, All Might smiled even wider. "My merch company has a new game in the beta testing stage. Would you like to try it?"

Tomura would play any games except All Might games. "Pass."

All Might peered down at him. "Are you feeling well, my boy? I don't mean to sound arrogant, but normally you would jump on the chance. Oh, dear, you look pale. I'm sorry for not noticing that you're sick! Should I take you back home?"

Tomura twitched. He was caught between All for One and All Might. "I'm fine, okay? Hit points at maximum, health bar full."

"Can I take your temperature?" All Might held out a hand toward his forehead.

Tomura ducked. "I have a headache."

All Might pulled out his phone. "I'll find the nearest pharmacy and buy some painkillers."

When Tomura got his hands on the doctor, he would wring his neck. Looking around, Tomura tried to find an opportunity to escape. He couldn't tolerate much more of this, but he also didn't want to arouse All Might's suspicions and get arrested.

A cloud of dust approached, ripping up pieces of the street. Tomura's own body bore down on him, at the center of the storm. Never before had he seen his own face so contorted with rage. The unholy light in his red eyes filled him with instinctive terror. Izuku Midoriya in his body bellowed, "TOMURA…SHIGARAKI…MUST…DIE!"

"Oh, no, you can't fight while ill." All Might scooped up Tomura. "I'll carry you somewhere safe, then fight the villain." He shot down the street.

Izuku pursued, screaming, "Now you're kidnapping All Might?!"

"All Might is kidnapping me!" Tomura protested, banging on All Might's back. "Put me down!" He'd rather die than be saved by his worst enemy.

Spittle and horrific growls flew from Izuku's mouth. Tomura stopped fighting, deciding maybe he'd rather let All Might carry him than face the madman.

With a groan, the street ripped upward. People screamed and fled. An unstoppable wave of destruction rose up around Izuku. Was he somehow unlocking an entirely new level of the quirk? Tomura felt a mixture of awe and terror.

A woman rounded the corner. For a brief moment, Tomura thought she was his grandmother. But no, he'd seen her face on the student's files. Inko Midoriya.

Inko turned toward the out-of-control mess of decay and shouted, "Izuku, calm down! You're getting dust on my shopping."

All Might said, "Ma'am, I have young Midoriya here." He held up Tomura like Rafiki presenting baby Simba. "Please get back, it's not safe."

Inko snorted. "I don't know who you're carrying, but that's my son." She pointed at the real Izuku. "I would recognize his feral snarl anywhere."

The wall of rubble collapsed. Izuku threw himself into his mother's arms, sobbing. "Mom…Bear Might…Bear Might was murdered!"

"There, there." Inko patted Izuku's back. "I'm sure I can fix Bear Might with a thread and needle. Haven't I repaired him after a hundred of your childhood games?"

All Might looked down. "Are you the real Tomura?" In seconds, he had handcuffs snapped around Tomura's wrists. "How dare you steal my successor's body?"

"I didn't do this!" Tomura protested. "I'll go quietly if you keep the feral brat away from me."

At this point, Tomura had developed suspicions about the body swap. He didn't think Garaki had intended this, but he was also certain an experiment to improve his quirk shouldn't have launched him into a different body. The doctor had been up to no good, and his sensei had been keeping secrets from him. Tomura was seriously considering defecting. Not the least because he'd never be able to respect All for One again after the waffle handfeeding incident.

Petting her son's borrowed head, Inko muttered, "I have my suspicions about who's behind this. Give me a moment to fix this." She sent a text.

No one would ever know exactly who Inko had texted. But anonymous equipment arrived the next day at U.A. to swap Izuku and Tomura back. Dr. Garaki fell down a flight of stairs. Inko repaired Bear Might, while All Might replaced all damaged items in Izuku's collection free of charge. Tomura got into therapy. All for One vanished from the villainy scene, and Hisashi Midoriya was home more often.

It couldn't all be good news. Izuku supposed given how much more peaceful his life had become, he could reluctantly tolerate his dad being around.

#

OMAKE TIME!

Garaki: My device will lock onto the consciousness of All for One—or anyone sharing his DNA. But that won't be a problem, because the master would have told me if he had a child.

All for One: …

Garaki: Wait, could the Ninth One for All holder have inherited scraps of the master's DNA through the quirk that once belonged to him?

All for One: Sure, let's go with that story. Also stand on top of the stairs.

#

Tomura: I never realized that your birth father was so terrible it drove you to All Might. I feel sorry for you. If All for One also acted so dementedly clingy and babying toward me, I might have been driven to the smiley menace for protection.

Izuku: That was a lot of All Might slander coming out of your mouth, but I'll forgive you because you insulted All for One more. For Bear Might…you will never be forgiven…

#

All for One: Ducky, since you have sensibly given up on All Might, I filled your room with my own custom-made merch instead. There's even an All for One bear. No need to thank me. Aw, he's so happy he fainted.

#

All Might: Thanks to your stolen knowledge of All for One's plans, and arrest of Tomura Shigaraki, we can save Japan.

Izuku: It wasn't worth Bear Might's sacrifice!