Not enough comic strips use theramin as a punchline.
The sound is often imitated — by a human voice, a computer, a bow drawn across the blade of a hand saw — but the theramin isn’t used, or even necessary. I’ll occasionally read the back story of a movie, tv show or pop song and discover that the wailing glissando was an uncanny imitation.* It’s as if the sound, once created, is free to roam the Earth like a shared mp3.
The slippery, operatic, chilling cry is the theramin’s ghost; a noisy spirit with a life long after the host is dead. Which is probably why it suited the score for Dark Shadows so well.**
*The Beach Boys’ “Good Vibrations,” for example.
**though, offhand, I don’t know if the sound was the ghost of a theramin, or the living instrument.