This quirk is probably the best quirk that I've thought of yet, I've thought of others before but, either I couldn't think of a downside for it, or it was just kinda... I dunno, just not great, but I think this quirk is actually pretty good, I dunno if there has already been someone who's thought of this, if you know of anyone, plz tell meh.
So the quirk gives the owner the ability to transform their shadow into a physical object, so like, you could make a scythe or something out of your shadow, BUT, it can only be YOUR shadow, you can't take the shadow of like, a building or something. What the objects look like: Well, they basically just look like the shadow of whatever the object is, except 3d and physical. Also, once the object is created, the user can manipulate it in interesting ways, they could make it stretch out to reach the opponent, they could change it from a scythe to a broadsword mid-swing, and stuff like that. And once you make something out of your shadow, your shadow disappears by however big the thing you made is, which is where it gets interesting.
The downside: You can only turn your shadow into something if your shadow is coming from natural sunlight, so if you're are indoors with artificial light from light bulbs and such, you can't use the quirk. Same goes for when it's night since you have no shadow when it's night. Another thing: You can only make the object as big as your shadow is, so if it's mid-day, your shadow will be really small, and you will only be able to make like, shurikens or a single spiked boot or something like that. Which makes you most dangerous during sunrise and sunset, when your shadow is super long, and you'll have insane range.
So, what do you think? I like it a lot, and do you have a name for it? 'Cause I suck at naming things T-T.