After looking up Spirited Away related images on Derpibooru, I’ve notice that some of the artwork use Fluttershy as Chihiro and Discord as Haku in his dragon form. So here’s my take on having to use this motive, by making an artwork that is like the shot in the movie of Chihiro underwater as she’s riding on Haku, and have it be Fluttershy underwater as she’s riding on Discord.
 
Okay, it’s not done as the exact same shot, but it’s close enough. And I think it look beautiful, much like the shot in the movie.
 
Originally drawn in pencil. Colors, filters, shading, lighting, and edits done in Photoshop.