In the second semester of 2013, I participated in a Creative Design Project. As project leader, I suggested the idea of developing a system for water quality control in an aquarium, which could be realized in the form of an underwater walking robot inspired by the hermit crab. Instead of adopting a typical solid material, I used silicon to construct the structure. As a result of the unique elasticity of silicon, the device had a soft texture and flexibility, so it was compatible with the marine life. Also, our team developed a feeler sensor using an ultrasonic sensor and micro switches, which was effective for an underwater environment. At the final presentation, the crab robot, which emitted blue lights and walked among goldfish in an aquarium, surprised my skeptical audience. Our team received the grand prize at Yonsei University’s 2013 Creative Exhibition. This robot, for which we have acquired a patent, also received more attention when it appeared on YTN’s Science TV program.