Your dragon is moon blue Malaemyth!
"blue Malaemyth" by Chris S. Baily
Your dragon is moon-blue Malaemyth. He'd tell you that himself, but he's – yawn – ever so tired...
Everyons' first reaction to Malaemyth is that he's a sluggish lazybones. And, true – of all his cohort, he's the most likely to be found with his eyes shut. But don't be fooled. At least, not entirely. Malaemyth might seem to be asleep, but he's probably just thinking. About why dragons come in five colours, or how people came to Pern, or how to calculate the circumference of a circle. (Something to do with pie, he tells you, though you're not sure what bubblies have to do with anything).
The thing is that Malaemyth is a lazy wher when it comes to stirring himself physically, but that's because he puts so much energy into thinking about things. And that's going to make him an oddity among his more vigorous classmates – and a tricky dragon to motivate into the required activities of training. But eventually you won't be weyrlings, and Malaemyth will be free to sit on his weyr ledge and think all day long.
But you'll have to be prepared to keep up with his abstract, dreamy notions...why do dragon names always end in -th, for example?