You need to use both hands at the same time to play the device, and notes are triggered by pushing on sections of a spiral raised area that wraps around both ends of the device in opposite directions. Each spiral represents a one octave jump, playing higher notes as it’s played closer to the outside edge.
The wires on the ends that look like a wire skull massager are actually used to anchor your hands so you can twist around the instrument. The UDAR outputs MIDI, so I guess that it’s more of a controller than an instrument in it’s own right, but it also means that you can use it to control any synth or MIDI device so you’re not stuck with just one set of sounds.
Unfortunately, as much as I’d love to have one of these, Michinobu has absolutely no plans to make these for sale, and his unit is a strict one-off.
Here it is in action: