Any viewer of My Hero Academia, dedicated or casual, thinks about what quirk they would want as their own. It's only natural to want one of the most powerful quirks. But on the opposite end, have you thought about which quirk you would absolutely not want under any circumstances? It's time to explore the worst quirks in My Hero Academia.
All quirks can be used to impressive effect if the user boasts a strong will and a creative outlook. Mirio Togata's Permeation is a great example of this - it's nearly impossible to use without serious risk, but through intense training, he turns it into a major asset. Still, the worst My Hero Academia quirks come with a ton of danger, are difficult to control, or are simply useless.
As underrated My Hero Academia quirks demonstrate, unusual quirks aren't always the worst. That said, the ones below are pretty awful.
Navel Laser Can Be Fatal If Overused
Firing a laser beam out from your belly button sounds fun - but only if you know you can control it. Yuuga Aoyama's quirk Navel Laser is potentially fatal, but less to villains than to himself. His lasers sometimes fire off randomly and are controlled by a special belt that he can't take off. Overusing his quirk causes stomach pain, and firing it imprecisely can damage his organs or even end his life. It's taken a lifetime for Aoyama to be able to use his quirk safely at all.
Sleep Gas Doesn't Come With Immunity
Sleep Gas could be an incredible quirk if the user were actually immune to it - and Mustard isn't. He creates and controls a harmful, sleep-inducing gas, but unless he wears a gas mask, he ends up just as affected as his enemies. While he boasts the advantage of planning ahead and bringing a gas mask with him to battles, if it gets knocked off his face, he's out of luck.
What's more, anyone who knows about his quirk - or who has a quirk that allows them to filter out toxins in any way - can easily avoid his attacks. Could this quirk be awesome? Sure. Is it? Not really.
You'll Eat Way Too Much Sugar With Sugar Rush
Rikido Satou's quirk, Sugar Rush, sounds pretty awesome at first - if he eats sugar, he gets super strength. While this sounds delicious, there are drawbacks. First of all, he increases his strength for three minutes per 10 grams of sugar consumed - that means drinking a can of Coke will buy him about 12 minutes. That could be enough for a short battle, but it may not. Also, the whole time he's using his quirk, his energy and mental capacity decrease, making him far less likely to make good decisions or escape a speedy enemy.
Also, the long-term health impact of consuming that much sugar is unclear. As a teenage boy who presumably suffers from no health problems, Satou is able to process it just fine - but will that always be the case? Excessive sugar intake over the long term makes you much more likely to develop heart disease, among other issues.
Bloodcurdle Presents A Major Disease Risk
Is Stain's Bloodcurdle a powerful quirk? Undoubtedly - when the user ingests a target's blood, the target becomes frozen for varying amounts of time depending on the target's blood type. While this proves useful in combat, it's disgusting and potentially dangerous in any other situation.
For one thing, this quirk exposes its user to bloodborne illnesses, of which there are many. Hepatitis A is easily transmissible through ingested blood. Though rare, it is possible to contract HIV through swallowing blood, especially if you have any open wounds in your mouth. While fighting an opponent, a Bloodcurdle user would have no means of checking on the health status of the person whose blood they consume. And those are just a few bloodborne diseases - think of all the other things you might contract by biting a rando's skin and drinking their fluids.
Paralyzing an opponent for a few minutes isn't worth all the potential health risks.