Don's shotgun went up. "Bob, we'll hold our ground. Is it--is he armed, can you see?""No! Can't tell."Armed! What nonsense! How could this wraith, this apparition, do us physical injury!"If--if he gets too close, Bob, by God, I'll shoot. But if he's human, I wouldn't want to kill him."The shape had stopped again. It was fifty feet from us now, and we could clearly see that it was a man, taller than normal. He stood now with folded arms--a man strangely garbed in what seemed a white, tight-fitting jacket and short trunks. On his head was a black skull cap surmounted by a helmet of strange design.Don's voice suddenly echoed across the rocks."Who are you?"The white figure gave no answer. It did not move."We see you. What do you want?" Don repeated.Then it moved again. Partly toward us and partly sidewise, away from the sea. The swing of the legs was obvious. It was walking. But not upon the path, nor upon the solid surface of these Bermuda rocks! A surge of horror went through me at the realization. This was nothing human! It was walking on some other surface, invisible to us, but something solid beneath its own tread.