":lepus" is an interactive digital art project that explores the connection between humans and nature through biometric sensors and visual representation. The project invites audiences to participate, allowing them to view and interact with the artist's heartbeat in real time. The concept is about transparent organisms. Humans have an internal and external world, the internal being bloody and dark red, never seeing the sunlight. We hide secrets within ourselves. In nature, animals protect themselves through transparent disguises. For humans, transparency means danger, fragility, and being exposed. By using transparency as a visual element, the project emphasizes the joy and danger of being transparent and allowing oneself to be seen by others in the deepest sense. Therefore, the project represents an imaginary transparent digital organism, displaying the artist Koi's heartbeat. It showcases oneself to the world in a transparent manner. The project uses a web page connected to the biometric sensor device worn by the artist. The biometric sensor collects real-time heart rate data and uses it to create a visual representation of the artist's heartbeat on the web page. This representation uses Three.js and shader technology to create an illusion of depth and motion with transparent organism imagery, showing the pulsing of the heart and reacting and changing according to the artist's heartbeat.