A Leyden ball is a fictional bullet used in a novel. In his 1875 science fiction classic Twenty Thousand Leagues Under the Sea, Jules Verne writes about an undersea hunting expedition using a very unusual form of bullet: "... the balls sent by this gun are not ordinary balls, but little cases of glass. These glass cases are covered with a case of steel, and weighted with a pellet of lead; they are real Leyden bottles, into which the electricity is forced to a very high tension. With the slightest shock they are discharged, and the animal, however strong it may be, falls dead."