If you don't know what a malfunction is, it's something that could harm them if their bodies weren't made for their quirks, like Dabi or Aoyama. Some of these are real, some are fake that I came up with. Dove is an example of a fake, Megami is real. These aren't like Tiktok malfunctions where they look like they're dying, some of them effect other, some effect theirselves.

Todomomo

Rei: Frost bite and Burns if she doesn't wear gloves. It's not something that's fictional because her body actually can't handle it sometimes.

August: things he makes can impale him if they come at him too fast. He got a scar on his jaw from this

Hino: Frostbite

Haruhi: can end up looking like Dabi

Eve: her lungs take a big belly flop and go "ew" if she doesn't get fresh air after using her quirk.

Kirimina

Both twins have skin like Mina's that are supposed to help with this. But their skin would melt if they were born with normal human skin.

Miruhawks

Um... really uncomfortable with this one.

Dove could go 'mad'. If you know why the March hare was crazy, same reason. I'll answer in comments if there are questions cuz I couldn't think of anything else but I don't wanna do this to my baby.

Iidamei

Tameiko could end up blind.

Kamijirou

Stormi could end up killing herself. Instead of the brain dead thing, she gets shocked repeatedly.

Dabi x Toga

Similar to what he does to other people, he basically boils his own blood.

Nejitama

Amai... she would have a tapeworm like thing where nothing she eats actually stays in her and she starves.

Phoenix, his stamina drains, just like Nejire :/.

Mt.Kamui

She starts having more and more resemblance to a tree. Her bones could harden completely, stuck in one place, etc.

Ryushot

This one is real.

Megami can end up being a cannibal. She might kill someone. Skin walkers can be animal like while in their human form.

Daenerys can have a sorta schizophrenic like thing where she thinks her dragon is constantly talking to her. That or it's similar to Tokoyami and it completely takes over her body and everything she does. No limit to it either, it stops when she passes out.

HitoRei

The stuff Rosalind lifts? People she controls? Idk.

Tetsukendou

Elliot literally needs to eat Iron.

SetSero

Idk

Shintati

Both kids could end up losing senses. Touch, sight, hearing. The vibrating also causes severe migraines.

This one is real.

Fatjoke

I- I DONT EVEN HAVE A QUIRK YET.

Midotsu

Mizumi doesn't really have one.

Mariposa can get impaled easily because she becomes weightless and can glide through trees so she could easily get impaled on a branch.

Clover, idk, thinking of having Izuku pass OFA down to her or one of Bakugo's kids.

Kacchako

Osoro can make his own eyes and ears bleed and it's happened before.

Okimi rips her own muscles apart everytime she overuses her quirk.

Micari

Micari has a small meltdown whenever he uses his quirk because of how loud it is, he'd prefer to be quirkless.

Millie knows whenever someone is gonna die. She can basically predict the future and starts screaming when someone she knows is in danger. She doesn't go deaf from it but like idk.

If you have any more, hand Em over cuz I was bored when I made this