[She watched whatever it was be put in. And within, what she saw was exactly what she expected to see. Unbeknownst to her, for now there was no consistent rule of how this worked, so her imagining that it would bubble and melt away like paper mush until it was just dissolved played out. She nodded in self-imposed acceptance.]

I think the white stuff is what it is before and after it breaks down. It takes substance and becomes things, with parts, but when it stops being the thing it turns into the white stuff...