The Navy’s robo-tuna, designed by Boston Engineering, is a 4-foot long unmanned undersea vehicle designed to blend in with marine life and perform military functions.

Watch: Engineering Update Episode 66: The Navy’s robo-tuna

This “biometric” autonomous vehicle moves just like a fish, flipping its tail to propel itself.

With its lithium ion battery, the bio-tuna can accelerate up to 40 knots and loiter for long periods of time. The applications include undersea mine detection and extended surveillance.