Boeing has been given a patent for a new kind of amphibious drone that's like something straight out of a classic spy movie. The aeronautics giant has a novel design for an unmanned aerial drone that can spontaneously convert into an unmanned submarine and go for a dive.

Boeing's take on a real world "transformer" begins with a drone that is launched aboard a large carrier aircraft and then separated near its target spot for entering the water. When the craft hits the water, some combination of its rear wings, stabilizer and one of its sets of propelling blades detach to make it more maneuverable underwater.

A buoyancy tank controls the depth of the craft underwater, while a second set of propellers are used for it to maneuver, allowing it to function essentially as other robotic submersibles at use today making payload deliveries or for reconnaissance missions. When the flying-turned-swimming drone surfaces, it can then transmit data back to its mission control.

To shed its heavy wings and stabilizer upon entering the water, the patent proposes the use of explosive bolts or a salt water-soluble glue to enable the detachment of flying mode-only parts.

The patent, which was filed in 2013 and granted by the US Patent and Trademark Office in April of this year, offers little else in the way of key specifications like what sort of motors and power sources the craft might use.

At this point, it would appear that this is really just a concept, as we've heard nothing about Boeing testing such a craft.

Then again, this is the same company that has already converted an F-16 fighter into a drone and pioneered unmanned underwater vehicles (UUVs), so who knows what it might be testing behind closed doors or beyond the public eye.