Researchers demonstrate that something interesting happens when a small drone with a spindly airframe spins at a high speed: it very nearly turns invisible. The spidery device is shown mounted in its launcher in the image above. The dark blur at the rightmost side is an outlet on the wall behind the drone, not motion blur from a moving part.

It’s called the Phantom Twist, and while we’ve seen single-motor drones that spin around a central axis before, they have always incorporated a wing-like structure or cleverly leverage the magnus effect to generate lift.
There’s not a lot of detail about the Phantom Twist’s hardware design but it appears to use a downward-angled motor for lift, relying on a high-speed control system to maneuver and maintain altitude.
This does away with the need for a wing, at the cost of only being stable while rotating at a high speed. We imagine it is also a touchy design that depends greatly on being balanced just so.
A hand launcher spins the device up before releasing it for flight. The visual effect once it is up and running is pretty striking; see for yourself in the short video, embedded just below.

If one dreams of invisible copters. Silly thinking.
Think twice.
The rotation of the blades of th main rotor creates a typical RADAR siganture anyway, called micro doppler signature.
Ok… now it’s time to add a persistence of vision system to that!!!! Floating holograms anyone?!?!?!
Nice idea, but don’t try to touch those “holograms” ;)