The theremin is perhaps the first truly electronic instrument. It is played without actually being touched. Instead, by moving one’s hands near the instrument, one changes the inductance of the circuitry and thus the resonant frequency, and so can control the pitch and the volume. It is not an easy instrument to master.
Here we see the Russian inventor Leon Theremin, who patented the instrument in 1928, playing it.
The sound of the theremin is frequently used to generate an eerie space-agey effect. Here we see 247 members of the Japanese Matryomin Ensemble use theremins hidden inside Russian Matryoshka dolls to play the Ode to Joy from Beethoven’s Ninth Symphony. It is pretty impressive to get so many to play in unison.
The Beach Boys song Good Vibrations used a variation on the theremin called the electrotheremin that is easier to play. Here is a studio recording session of Good Vibrations. You can hear the theremin-like sound first at the 0:54 mark and again later.