Final answer:
The author's use of descriptive phrases creates a dark and eerie atmosphere in the passage through vivid imagery and sensory language.
Step-by-step explanation:
The author's use of descriptive phrases such as marrow-freezing incident, demoniac laugh, and unnatural sound in paragraphs 2 and 3 contributes to the overall meaning of the passage by creating a dark and eerie atmosphere. These phrases evoke a sense of fear and unease in the reader, helping to establish a mood that aligns with the tone of the passage. The vivid imagery and sensory language used in these phrases add depth and intensity to the description, making the reader feel as if they are experiencing the events of the passage firsthand.