to recap: It is not living, is not a location, is not an item, is a small part of the story, is on disc 1, is in either Alexandria/Treno/Lindblum/Cleyra, is not smaller than Vivi, and is a one-time thing.

Because it's one-time, I'm guessing it's in Cleyra (that's not a question, it's me thinking out loud). But it's not alive, and it's not an item, so it would have to be...something involving the sand in the tree trunk?

That's my question. Does it involve the sand in the tree trunk?