Sun Wukong was sealed and defeated the Buddha, and entered the Lingshan Mountain. At the Buddha's Enlightenment Ceremony, he noticed something strange - the Tathagata's sermons made his spirit faint, and his golden crown shrank with his blood, like a living thing. He used his spiritual consciousness to probe into the crown and found that there was an eight-character mantra carved on the skull: "The golden cicada enters the shell, and the battle becomes a puppet."
It turns out that the "universal salvation of all sentient beings" claimed by the Lingshan Buddhas is a big lie. All the souls that have been transcended have not entered reincarnation, but have been thrown into the "karma pool" underground in the Lingshan Mountain, and turned into nutrients to maintain the immortal golden bodies of Buddhas. Nine-nine-eighty-one is just a carefully arranged script, just to harvest the souls of the strongest people in the three realms to Lingshan. There is no compassion here, only a fat Buddha; there is no salvation, only filthy offerings that suck the soul.
Tang Monk had already seen through the truth, but was silenced by Jin Chanzi's old oath; Bajie pretended to be crazy and acted like a fool, secretly delivering information to Wukong; Sha Monk had been silent for five hundred years, with fragments of the ancient scripture hidden in his belly. Wukong took off the golden crown, forced the Buddha bones out of his body, and went to the Lingshan Mountain to kill him. Every time a Buddha is killed, a piece of imprisoned karma returns to its original owner.
In the final battle, Sun Wukong faced Tathagata without evading or dodging, and thrust the golden cudgel into his chest, detonating the stone heart that Nuwa had planted in his body when she mended the sky.