I've always really loved any sort of blue with iridescence or an ocean blue with hints of aqua, this is the closest I could get.
I also like to tell or give the impression of a story with my dress ups, so in the case of this one, I like to think that it is some sort of magical creature that would live in cold climates, near an ocean or sea, visiting people in their dreams and granting wishes to those who manage to catch it.