Hostility Displacement
Hostility displacement is expressing aggression to someone (who did not cause the hostile emotion) from a lower authority. In this defense mechanism, one cannot show his or her hostility to the one who caused it so it gets displaced to a victim who is less threatening. For instance, Joe's boss got angry at him. He then went home and beat his wife for no reason. Similarly, Joe's wife cannot express her hostility towards her husband so she kicked their dog. This is one of the reasons that leads to domestic abuse.