Your home is supposed to be a safe place, a space that gives you warmth and comfort. So, imagine looking up at the ceiling of your home and finding something that looks like this. According to the OP, it was growing “at a very rapid rate” and leaving grayish particles on the table below.
If it was us, we would just leave and never look back. Of course, the OP was curious to know what this actually was. Someone pointed out that those were the studs from the walls being redistributed by termites. Yep, just resident termites redesigning the house as they usually do without asking anyone. Anyone else getting the shivers?