A new robot demonstrated ... with its near silent tail fin propulsion system, and this robotic fish transforms into a stealthy surveillance machine. The Robo-Shark is about six feet long ...

How about an underwater drone that looks like a shark? What about if it is powered by a robotic tail fin that simulates the ... company called Boya Gongdao Robot Technology. The company say ...

but next time you're at the beach and see a fin sticking out of the water, it might be a killer shark—or it might just be a Navy robot.