Bob Stone - also known as "The Mole" - is a Nobel laureate in biochemistry who designed and maintains Eureka's underground utility systems (air conditioning, water, waste processing, etc.). He based the design on the human digestive system and is the only one in Eureka who completely understands its inner workings. According to his wife, Bob can spend days down in the tunnels underneath Eureka. When he does resurface, she is always glad to see him.