1. Bloodthirsty Bat: The core design is inspired by the bat, often associated with darkness and mysterious power. The bat's wings are elegantly curved, creating a sense of movement and depth, symbolizing the nocturnal hunter, while the sharp edges of the wings represent its bloodthirsty nature.

2. Red Zirconia Eyes: The bat's eyes are set with striking red zirconia, symbolizing blood and passionate desire. The fiery glow of the red zirconia represents endless longing and energy, enhancing the visual impact of the design. The red pupil makes the eyes look sharper and more aggressive, conveying a dangerous yet alluring attraction.

3. Contrast of Darkness and Light: To highlight the bat and red eyes, the tunnel itself is crafted from tungsten steel or other metals with a deep black or matte finish, creating a strong contrast of light and shadow. This design emphasizes the bat's dark essence, making the red zirconia eyes stand out even more.

4. Intricate Carvings: The surface of the tunnel could feature detailed engravings of the bat’s wings, claws, and body outline, enhancing the overall dimensionality and complexity. These details add layers and artistic flair, making the design appear more personal and powerful.

5. Symbols and Emblems: The design could incorporate elements related to blood, the night, and mystery, such as shadows, stars, or abstract blood drop patterns, further enhancing its allure and mystique. The overall design exudes dark romance and strength.

This design combines mystery, power, passion, and individuality, making it perfect for those who embrace unique, dark aesthetic styles in their jewelry.