Resumen
The article is a study of the evolution of the resolution of the biblical root theme of the episode inserted in the Genesis narrative of the fratricide between Cain and Abel. In terms of language and culture, reference is made to the Iberian world and especially to Catalan. Within this tradition, mention is made, in the medieval period, of the weapon that causes and favors homicide (the jaw of a quadruped) and in the contemporary world the reverse that inverts the roles of victim and executioner.