Dr. Erhardt and Dr. Forrester in “The Robot vs. the Aztec Mummy”

[while introducing their creation for the Invention Exchange, a chalkboard vinyl on a record player] Okay- so you're throwing a party, it's 3 AM, and none of the guests are leaving. That's when you bring out the Chalkman!

Yes, as every self-respecting scientist knows, the sound of human fingernails on a chalkboard is most annoying. It initiates the primal fear response in all mammals, much like a chimpanzee scurrying across the plains of the Serengeti. Simply put your Chalkman on the platen. [shows record] Now this is a real chalkboard. (Set on) Side B; excellent. And you'll just notice the tonearm has real human fingernails embedded in the hand, now place it on the platen... [scratches the disc, creating a shrill sound] Now open it.

They'll stay.

Close it. [shrill scratching sound continues]

They'll leave.

And so on and so forth.