For this drawing I sketched out everything first on index cards, photographed them, then pulled them into Photoshop and traced them:

We’ll pretend that the guys are supposed to be ghosts or something. :) And that the one on the right has really long limbs. If I had more time I would have stippled the rock textures, but instead I used a large brush, which unfortunately gave a very obvious repeated look. (I should have randomized the variation. Next time…)
Throw in your two cents