Some of you might have wondered a little bit about what these creatures were when you watched Princess Mononoke~
In Japanese folklore, they are called “Kodama“, or tree spirits. (◡‿◡✿)
They inhabit trees and are sometimes called “protectors of the forest“, because it is said that they curse anyone who destroys the tree that they are living in.
In some places in Japan, it is said that when a tree reaches 100 years old, it instantly produces its own spirit, thus becoming a kodama itself. Such trees are considered sacred, and are marked with a shimenawa (enclosing ritual rope).
Kodama are sometimes portrayed in old tales as human-like yokai, which stand guard beside the tree, and sometimes interact with unknowing passers-by.
In Japanese folklore, when a person disappears mysteriously, he or she is said to be taken to the spirit world, or has been “spirited away”. *wink* ( ´∀｀) It is also said that when a person comes back from being spirited away, he/she is now a new and better “enlightened” person than before.
In Hayao Miyazaki-san’s film “Spirited Away“, Chihiro started to become “see-through” upon prolonged exposure to the spirit world. Haku then gives her a bit of spirit food that helps her from disappearing and makes her one with the spirit world, because according to Japanese folklore, if someone eats food from the spirit world, they are then allowed and bound to stay, until a powerful spirit releases them from their curse. (︶ω︶)