[alexhornbake]

Common mistake. Good vibrations did not actually use a theremin. It was a ribbon controller type instrument that was designed to mimic the sound. Theremins are hard. https://en.m.wikipedia.org/wiki/Electro-Theremin

[Stratoscope]

Somewhat fittingly, the Electro-Theremin is seen being played at 4:20 in the Brian Wilson interview that gibspaulding posted:

https://youtu.be/j_0WmqnC6eA?t=257

[Nition]

In terms of actual Theremin music, here's Clara Rockmore's Nocturne In C# Minor [1975]: https://www.youtube.com/watch?v=ghWdgcYIcSk