It was an unfortunate remark, for the dragon spouted terrific flames after him, and fast though he sped up the slope, he had not gone nearly far enough to be comfortable before the ghastly head of Smaug was thrust against the opening behind. Luckily the whole head and jaws could not squeeze in, but the nostrils sent forth fire and vapour to pursue him, and he was nearly overcome. He stumbled blindly on in great pain and fear. He had been feeling rather pleased with the cleverness of his conversation with Smaug, but his mistake at the end shook him into better sense. 'Never laugh at Live dragons, Bilbo you fool!' -The Hobbit.