Gnomes - Very small creatures that live in holes in gardens. They have leathery skin and large bald heads. To de-gnome a garden, grab the gnome by the ankles and swing it around your head, and then throw.
Gnomes live ten times faster than humans. They're harder to see than a high-speed mouse. That's one reason why most humans hardly ever see them. The other is that humans are very good at not seeing things they know aren't there. And, since sensible humans know that there are no such things as people four inches high, a gnome who doesn't want to be seen probably won't be seen... Wings