curdle

This term describes a sudden, undesirable change in texture where a smooth liquid becomes chunky and separated. It carries a strong sensory association with spoilage or chemical failure, often evoking a feeling of disgust or a sense of something gone wrong in a culinary context.

When used figuratively, specifically in the phrase "curdle the blood," the word shifts from a physical process to an emotional reaction. It captures the sensation of freezing in terror, suggesting that fear is so intense it physically alters the body's internal state, turning fluid motion into a stagnant, clotted mass.