It had no internal power supply, it worked like an RFID tag, but it was electronic.
Tangentially, I didn't know this (from Wikipedia):
> The Thing was designed by Soviet Russian inventor Leon Theremin, best known for his invention of the theremin, an electronic musical instrument.
Yeah I was going for no battery
Idk though when I read it, it seems like it's literally an antenna attached to a can "resonator" is that electronics? It is I guess since it can carry an RF wave? Electronics I think of a chip or circuitry. I get it has to be some form of a circuit to work even as a monopole.
The article says it though: "...hung in his office behind his desk, and which contained an electronic device"