Nhim nods again, then rears her head back, her fins bristling automatically. The dragon suddenly makes a noise that's halfway between a hacking cough and roar, and a black, slimy glob of something flies out from her jaws, landing with a splat several yards away. (Its appearance is probably nature's way of saying 'DO NOT TOUCH'.)

The reason for that becomes apparent seconds later, as the acid works through its protective coat and begins eating into the ground, smoking and hissing.