What put a stop to all this was a sudden fright. Shasta discovered that someone or somebody was walking beside him. It was pitch dark and he could see nothing. And the Thing (or Person) was going so quietly that he could hardly hear any footfalls. What he could hear was breathing. His invisible companion seemed to breathe on a very large scale, and Shasta got the impression that it was a very large creature. And he had come to notice this breathing so gradually that he had really no idea how long it had been there. It was a horrible shock.