Read the passage from Animal Farm. Napoleon decreed that there should be a full investigation into Snowball's activities. With his dogs in attendance he set out and made a careful tour of inspection of the farm buildings, the other animals following at a respectful distance. At every few steps Napoleon stopped and snuffed the ground for traces of Snowball's footsteps, which, he said, he could detect by the smell. He snuffed in every corner, in the barn, in the cow-shed, in the henhouses, in the vegetable garden, and found traces of Snowball almost everywhere. He would put his snout to the ground, give several deep sniffs, and exclaim in a terrible voice, "Snowball! He has been here! I can smell him distinctly!" and at the word "Snowball" all the dogs let out blood-curdling growls and showed their side teeth. The animals were thoroughly frightened. It seemed to them as though Snowball were some kind of invisible influence, pervading the air about them and menacing them with all kinds of dangers. How does the characterization of Snowball best support the author’s purpose?