Undulatory locomotion is a unique form of swimming that generates thrust through the propagation of a wave through a fish’s body. The proposed device utilizes a constrained compliant material with a single actuator to generate an undulatory motion. This paper draws inspiration from Anguilliformes and discusses the kinematics and dynamics of wave propagation of an underwater robot. A variety of parameters are explored through modeling and are optimized for thrust generation to better understand the device. This paper validates the theoretical spine behavior through experimentation and provides a path forward for future development in device optimization for various applications. Previous work developed devices that utilized either paired soft actuators or multiple redundant classical actuators that resulted in a complex prototype with intricate controls. The work of this paper contrasts with prior work in that it aims to achieve undulatory motion through passive actuation from a single actively driven point which simplifies the control. Through this work, the goal is to further explore low-cost soft robotics via bistable mechanisms, continuum material properties, and simplified modeling practices.