Behavioral diversity is one essential feature of living systems in order to exhibit adaptive behavior in hostile and dynamically changing environments. However, classical engineering approaches strive to avoid the behavioral diversity of artificial systems to achieve high performance in specific environments for given tasks. The goals of this research include understanding how living systems exhibit behavioral diversity and use these findings to build robots that exhibit truly adaptive behaviors. To this end, we have focused on an amoeba-like unicellular organism, i.e., the plasmodium of true slime mold. Despite the absence of a central nervous system, the plasmodium exhibits versatile spatiotemporal oscillatory patterns and switches spontaneously between the patterns. Inspired by this, we build a real physical robot that exhibits versatile oscillatory patterns and spontaneous transition between the patterns. The results are expected to shed new light on the design scheme for life-like robots that exhibit amazingly versatile and adaptive behavior.