C707 A Life and Death Moment

Not far away, in an inconspicuous corner, there was an oval-shaped stone embedded in the stone wall. The stone was not big, only the size of a palm, and the top was abnormally sharp, like a sharp sword. The light shone on it, emitting a cold light. The stone was also grayish-black, and it was completely the same as the surrounding stone wall. If one did not look carefully