He is variously called cythraul, dera, diafol, all euphemisms for devil, equivalent to our destroyer, evil one, adversary--as well as plain diawl, devil. In his character of a familiar spirit he assumes the shape of a fiery ball, a donkey, a black calf, a round bowl, a dog, a roaring flame, a bull, a goose, and numberless others, including the imp that goes into a book. In all this he bears out the character given him in old mythology, where he grows big or little at pleasure, and roars in a gale as Hermes, the wind-god, howls as a dog, enters a walnut as in the Norse Tale, or is confined in a bottle as the genie of the 'Arabian Nights.'