Somebody mentioned something about an Appa hat (from The Last Airbender), so I just had to look around and I found it!
Holy crap, that’s sick! This is a handmade item, and I don’t know if it’s just one person or a group of people making them, but this seller’s store for more info. They have other cool, geek designs too, like that beard beanie I’ve seen around so many times, a viking beard hat with horns, and even a Cthulhu ski mask, among other cool things.
Winter is coming, so I’m considering ordering one of them cool hats, for reasons.