The Dream Eater Technique is a Ninjutsu technique that is used with Genjutsu techniques. It can only be used if the target is already in a Genjutsu. It allows the yin energy that is creating the Genjutsu the victim is currently in to feast on the target's mental and spiritual energy to weaken their defenses against Genjutsu and increasing the power of the Genjutsu. The technique can also inflict physical damage because of how it destabilizes the chakra in the body through the lowering or lack of mental energy to force the opponent's own chakra to attack their body. If the target is drain dry of their mental and spiritual energy it could lead to their untimely demise. However, this takes a long time.