So I did a bit more sketching about and came up with this, though I realized that I was kind of drawing Yagdra from Starcraft II, who happens to be a half-melted (why?) volcanic worm, and that bothered me to no end.
I looked at some pumice, but between the lateness of the hour and my irritation with myself over perceived unoriginality, I didn’t have the heart to stipple in nor draw a bunch of crevices. I’m still not sure how to make obsidian look like obsidian as well as dragony bits.
All that having been said, I do like this piece, and would/may eventually sit down and annoy myself a little further trying to paint it.