In the forest, there are some mushrooms everywhere, some of them are shimmering. Apparently there are Mushroom Spores and Glittering Spores that can be picked up off of them. If you hit them, a puff of the stuff comes off but nothing is actually gathered.
Is it even possible to pick these up? If so, will I need certain items? How can I do it?
Fi mentions at some point in the game that you could get some when I returned to the forest but I wasn't really paying attention to what she said on how and never figured out myself.