Negurono Zoou Bidyun is Jiiza's ultimate spell. He summons a gigantic monster with circular mouth, multiple faces, and many tentacles with mouths at their ends, and throws it at the enemy. It was used only once in the Gaiden chapter "Friend", to destroy Zatch and his friend Muumu. However, The red book appeared to Kiyo in the human world at the last second and he and Zatch effortlessly ripped apart the spell with Bao Zakeruga, and defeated Jiiza.