In Midnight in the Garden of Good and Evil, the now-classic account by John Berendt of his time in Savannah, Georgia, there is a character named Luther Driggers. Luther – real person but his name in the book is a pseudonym – was a scientist who invented the flea collar. In the book Berendt accompanies him as Luther tries to market glow-in-the-dark goldfish (the scheme bombs bigtime). But his real claim to notoriety is that he possesses a bottle of poison so deadly, that it would kill every man, woman and child living in Savannah. He never intends to actually use the stuff. But Luther enjoys the sense of power that comes with owning so potent a thing, knowing that his fellow citizens are terrified out of their wits that Luther will pour it into the water system some night when he’s depressed or drunk or something.

Well, it’s ...