How does Preston use imagery to create mood in the following lines (make sure you also mention what you believe the mood is)?

"The monkeys' bodies were visable in the clear bags. They froze into contorted shapes with their chest cavities spread wide and their intestines hanging out and dripping red icicles. Their hands were clenched into fists or open like claws, as if they were grasping at something, and their faces were expressionless masks, their eyes glazed with frost, staring at nothing." (179)