The Mad Gasser of Mattoon and Gef the Talking Mongoose

Until the idea of space flight became credible, there were no aliens; instead there were green men who hid in the woods. In the same way, psychotic delusions keep up with scientific change: the people once pursued by phantasms of the dead are now pestered by living celebrities who watch them from inside their TV sets, and those who used to confess themselves possessed now say there is a bomb inside them. The dictionary attests to the power and antiquity of the need to believe we are sharing the planet with beings not animal and not human, with ‘little greys’ from spacecraft, with goblins and domestic deities: beings who suspend the laws of nature wherever they pop up, and suspend moral laws too, for household sprites and pucks often have a fierce, childlike sense of justice, and retaliate without fear if they are slighted; aliens who want sex never ask nicely. On the lonely road by moonlight, the parts of ourselves oppressed by our intelligence come out to play. We meet ancestral selves, neither gods nor demons but short semi-humans with hairy ears and senses differently attuned – the eyesight of an eagle, the nose of a hound. The phenomena are internal, generated by the psychological mechanisms that connect us to each other and to our evolutionary past.

-- from Hilary Mantel's review (24 Jan) of the Chambers Dictionary of the Unexplained. She says that "Only a few entries feature sentences like: ‘The aliens returned, exchanging barking sounds with one another as they stripped him naked and sponged him down.' "