I used a shell stitch for the hat using the method of the simple shell cloche and then made the spikes. Then I crocheted a simple tube that increases every few rows for the tail.
I'm still trying to think of ways to make it look more dragon-y and less dinosaur-y. Wings were suggested, but I don't know how to create wings that won't flop and look ridiculous (anyone wearing a dinosaur hat would NOT want to look ridiculous, right?).