The Yasabi is a rust like mushi. They are harmless and attach themselves to the body of dead animals and help in their decomposition during this process they make a specific sound. Whenever they hear this sound anywhere, they travel to the sound's place of origin in search of food. But if no food is found they attach themselves to anything including living beings.The attachment of the mushi makes the host have stiffness in the joints and sometimes cripple them. Weakness The yasabi dont have any real weakness.