For example in Bayonetta (video game series) the witches there channel their magic through their hair, they also weave their clothes with their hair strands. So it (kind of) makes sense that the top layer of clothes disappears when they do their big summons since the demons they summon are gigantic and are ensnared in their hair. In my current project Kitsune are like regular humans for the most part (aside from the magic) but their bodies are naturally far more dense. They have to be molecularly dense to contain the magic they hold, their bodies would be torn apart inside and out otherwise. (it also explains why they are so long lived, at some point magic just causes their internal clocks to just stop and they no longer age. And since they can't age, less chance of organ failure etc) An average kitsune weighs 2.5 times more than an average human of their build type.