My Hero Academia's Mt. Lady, Yu Takeyama, is one of the first pro heroes we ever meet with the flashy Quirk of Gigantification. Able to become a giant in a matter of seconds, Mt. Lady can easily go toe-to-toe with any massive villain, while still managing to attend the galas and hero events along with the little people. Here then, are five strange secrets about Mt. Lady's mountainous Quirk.
Mt. Lady's Gigantification Only Has Two Settings -- Giant and Average
Gigantification offers a lot of potential for use in various settings, whether fighting a kaiju-villain in the city, or dealing with a falling cliff in the country until rescue crews get everyone out safely, growing large and taking charge means that there's nothing too big for Mt. Lady to handle -- too bad there's quite a few things too small. As revealed in Volume 3, Bonus Chapter 2, Mt. Lady's Gigantification Quirk only gives her two sizes to choose from: her normal height of 162 cm, or her giant height of 2062 cm. This means that she requires a certain degree of space to move effectively, and the narrow streets of the city severely limit her ability to fight. While she could theoretically make use of transitioning between her sizes to temporarily grow smaller to dodge attacks or fit through narrow spaces, the constant switching would be extremely tiring, and may give the villain the upper hand.
Gigantification is An All or Nothing Deal for Mt. Lady
Another drawback to Gigantification is that she has to apply it to her entire body at once, which means that she can't imitate Class 1-B Itsuka Kendo's Big Fist Quirk by enlarging her hands, or likewise only enlarge her foot at the end of a kick to increase her power during an indoor struggle. While this would inevitably create a fair amount of property damage -- it's not as if going completely giant doesn't -- as Volume 3, Bonus Chapter 2 also revealed, she's had to rebuild her own agency as a result of her Quirk activating while indoors. While the ability to channel her Quirk into certain body parts would let her mitigate the drawbacks of using it inside, it's probably for the best she can't -- a "gigantified" limb would gain huge amounts of weight and become somewhat unwieldly, especially when you consider that...
Mt. Lady's Gigantification Quirk Only Gives Her Super-Strength in Her Giant Form
While using her Quirk, Mt. Lady can lift cars, buildings and other large items with ease -- in her human-sized form? Not so much. It may also be that what appears to be super-strength is simply her muscles scaling up with the rest of her, making them proportional to her size. While Mt. Lady is a force to be reckoned with while using her Quirk, the moment she de-sizes, previously harmless villains may be able to overpower her.
This also means she can use her Quirk defensively -- as she can make use of her giant-strength to deflect potential lethal blows and turn them into minor wounds. She's even seen doing something similar in the manga, where in Volume 11, Chapter 91, she grows to block Mr. Compress' pursuit of the 1-A kids, and the impact simply gives her a nosebleed, rather than the broken bones she probably would have suffered had she collided with him in her small form.
Gigantification Only Affects Mt. Lady And Nothing Else
Mt. Lady must have had some interesting times learning how to use her Quirk growing up -- as her Quirk only affects her body, not her clothes, nor anything else she's touching. As a result, her hero costume, much like many other heroes' was specially made to grow and shrink with her, which may explain why it's so skintight. Being as tight as possible means that when she grows, it has to stretch less, which may have made its construction easier and more reliable. It's also a relatively safe bet that she wears her hero costume or some form of bodysuit under her civilian clothes on her days off, as strong emotions can sometimes cause her to inadvertently activate her Quirk.
Gigantification Lets Mt. Lady Break the Laws of Nature
Mt. Lady's Gigantification Quirk is something that many of today's scientists would be blown away by, at least in part because it manages to break one of the most basic rules of nature: the law of conservation of mass. The principle is simple: there is a fixed amount of matter in the world, and everything that is was created using something else. For example, if you evaporate one litre of water, the molecules don't vanish, instead the liquid H2O breaks down into an equal amount of the gases H2 (hydrogen) and O (oxygen.)
Mt. Lady completely destroys this natural principle when she uses her Quirk. Instead of becoming lighter as she grows, spreading her original mass throughout her giant form (or condensing her giant-form's mass and weight into her small form), she becomes heavier, implying that she's gaining mass, which she then loses when she returns to her default form. While this is impossible for our world, there are some potential explanations; Mt. Lady has already been shown to be a bit of a big eater, with a love for high-carb snacks like Takoyaki. Much like Fat Gum, her body may convert these foods and their energy for use as part of her Quirk -- though unlike Fat, the extra calories don't show up until she activates Gigantification.
Another possible explanation is a little more far-fetched, but would explain why transforming doesn't cause a windstorm every time she grows or shrinks -- simply, her Quirk has a second factor whereby she converts the air that would have been displaced by her sudden growth into body mass. Likewise, the converted air is returned upon shrinking, explaining how she manages to stay a reasonable weight.