This paper presents the mechatronic issues of an amphibious robot capable of multi-mode motion, entirely inspired by some impressive propulsion solutions offered by the Nature. Considering that the oscillating fin utilized by fishes and cetaceans is an efficient propulsive mode under water and wheel is another formidable opponent on ground, a multi-purpose, amphibious propulsive mechanism that combines carangiform or dolphin-like swimming and wheel-like motions is designed. Based on the module-based structure, the robot is composed of a head, multiple identical propelling-units, and a flapping foil, which allows for flexible propulsion, reliable maintenance, as well as scalable fabrication. Further, an ARM-based embedded control system is designed and corresponding motion control algorithms are addressed. Preliminary experiments with the prototype finally validate the effectiveness of the multi-mobility mechanism and control.