"If you do not yet know who the Nac Mac Feegles are: 1) Be grateful for your uneventful life; and 2) Be prepared to beat a retreat if you hear anyone as high as your ankles shout “Crivens!” They are, strictly speaking, one of the faerie folk, but it is probably not a good idea to tell them this if you are looking forward to a future in which you still have your teeth."