It was the sort of grin people use when they stare at your left ear and tell you in an urgent tone of voice that they are being spied on by secret agents from the next galaxy. It was not a grin to inspire confidence. More horrible grins had probably been seen, but only on the sort of grinner that is orange with black stripes, has a long tail and hangs around in jungles looking for victims to grin at.
(The Light Fantastic)