Those who travel between worlds are advised to limit their interactions with the inhabitants of foreign worlds in order to maintain the world order. For this reason, the main characters change their appearance in certain worlds to avoid standing out. In the worlds based on "The Little Mermaid" and "The Nightmare Before Christmas", Sora, Donald, and Goofy transform into undersea creatures and Halloween monsters, respectively. For "The Lion King", they transform into savannah animals because Nomura felt that it would appear odd to have Sora and the others interact in their standard forms, since no humans appear in that film.