Final answer:
In the movie Spirited Away, Chihiro discovers that Haku has become a white dragon while encountering the spirit world.
Step-by-step explanation:
The question is related to the movie Spirited Away, which falls under the subject of Arts. In the movie Spirited Away, while encountering the spirit world, the protagonist Chihiro discovers that Haku has transformed into a white dragon. This transformation is a pivotal moment in the story and holds symbolic significance.