The low whistling sound did not have changes in its tone. It was a bit like the sound of a train whistle that had been lowered. Xiao Lin suddenly increased his alertness, but he was not surprised. From the start, they were already prepared for the fact that some powerful beasts would be hiding in the forest, as that would likely be the hardest point of this examination; it was just that it appeared a little later than they anticipated.
However, the cry was a little odd, and when Xiao Lin tried to determine where it was coming from, he was surprised to find that the sound constantly changed in distance, as if it were floating about. What caused them to be even more in disbelief was that, at the nearest point, the sound sounded like it was right next to them!