Engineers and designers often draw inspiration from nature. Look at this vehicle – Submarines Honda USS- 299.
Source of inspiration designer was chosen very unconventional creature – stingray. Yes, not everyone this beast may seem attractive , but as a model for the submarine it fits well, is the nature knows exactly what should be the form of a machine designed to travel at great depths. Technical characteristics of the submarine absolutely not interesting for the author, but can hope, that they might interest the company Honda, which ( who knows?) wants embody this concept to reality.