Can you imagine how horrified it must be for nrc when the magicless yuu, suddenly overblot and raised these blot crystals after unknowingly absorbed the excess blot like an air purifier
Or their overblot form is a horrendous beast like the witches from madoka magica or the obscurus from fantastic beasts and where to find them
okay TW! for descriptions of intense pain and bodily harm, emotional distress, a panic attack, and brief suicidal thoughts.
In my headcanon, blot causes burns and the like (see this post for more details). So, if Yuu did overblot, it would be a HORRIFIC mess.
When it first starts, it's because Yuu was arguing. Their emotions got a little out of control, and suddenly they just... stop talking. Confusion overwhelms them as their nerves start to tingle, and they feel something warm drip down their face. For a second, they think it's blood.
Blood isn't black. Blood doesn't smell like this- like burnt tar. Blood doesn't sear your skin when it rolls over it.
The realization sets in. They look almost panicked, wiping the blot off of their face and staring at it in terror, before recoiling as the true pain sets in. They're trying to calm themself down, to stop this before it starts, but it's too late.
The blot is gushing now. Never has it been given such easy fuel- there is no magical resistance. But this fuel is short term. It won't last long. Not like magic does.
Yuu is full panicking at this point, tears mingling with the inky black liquid as they crumpling, pain and sobs racking their body. They can't stop this. They can't do anything. And it hurts. It hurts so bad.
The blot is burning their skin where it touches, searing pathways into the flesh. Steam is coming off of their skin in slight amount where the blot is cooking it. If the pain isn't sending Yuu into hysteria, the smell will.
At a certain point, the blot is more in control than Yuu is. Their body is covered, their sobs are muffled, and they're a cowering, writhing mess underneath the much larger, much more imposing, swirling mass of the inky substance. Whatever STYX thought they knew about phantoms is blown completely out of the water, because by the Seven, what is that thing.
All the while poor little Yuu is stuck, burning alive, screaming incoherently in agony, crying, and begging for someone to just end their pain.
And all it sounds like is a mass of bubbling tar- because, right now, that's all they are.