[Refugee]

My 3 transistor DAV stick does exactly the same when you run it along a flex.
I liberated it from a skip in the 1980s. It was the same skip I liberated lots of valve mono block amplifiers from on another day. I still have four of the amps.

The DAV stick is an early example of a capacitive volt stick built to a circuit like the ones in the electronics magazines with a square hole to shove the 9 volt battery into. A round PP4 was found in it. 20 years later I de canned a 6XAAAA cell PP3 and taped it into a round shape and dug into a box of samples I had that contained of all things some uncrimped PP9 snaps.
It was a quick fun restore and works as well as a modern one.