The Redcap is an old goblin said to dwell in the ruined castles and watchtowers along the England–Scotland border, who must kill travelers and dye his cap red with their blood. Should the blood in his cap dry, he himself withers, so he cannot stop killing.
The compulsion to kill endlessly because stopping means death, joined to a curse bound to a single place, makes him an archetype of the uncanny in which violence perpetuates itself.