Pigsy was lazy, stupid, greedy.He succeeded into becoming an immortal and ascended to Heaven. He was given the title of Tian Peng Yuan Shuai and was in charge of the Heavenly River.
But one day, after attending the Empress's Peach Banquet, he became very drunk and stumbled into the Guang Han Palace, which is the abode of the Moon Goddess, Chang Er. Because he was drunk, he flirted boldly - very boldly - with Chang Er. Someone reported this to the Jade Emperor and troops surrounded the Guang Han Palace immediately. He was captured and brought to the Jade Emperor. Luckily for him, the God of Venus came forward and asked Jade Emperor to lighten the punishment. So instead of death he was given 2000 strikes of the hammer and exiled from Heaven.
Being the clumsy oaf he was, he went onto the wrong road and was accidentally reincarnated as a pig on Fu Ling Mountain, named Zhu Gang Lie. On the mountain, there was a woman called Sister Luan living in Yun Zhan Cave who let him live with her. Unexpectedly, she died a year later, leaving the cave and everything in it to him. Ba Jie lived on humans until the Goddess of Mercy passed by. She asked him if he was willing to protect the monk of Tang on his pilgrimage to the West. When Ba Jie said yes, she gave him the Buddhist name of Wu Neng and left. Ba Jie waited obediently for Tang San Zang, while obeying the eight prohibitions of Buddhism.
One day, he heard that a wealthy man surnamed Gao from the village nearby was offering his youngest daughter's hand for marriage. Ba Jie went and persuaded old Mr. Gao to accept him. He eventually became a nuisance to the family because he kept showing his true form, an ugly pig demon, sullying their reputation. When Mr. Gao wanted him to sign the divorce documents and leave, he locked his wife up in the rooms in the back yard. Finally, the pilgrims arrived and Wu Kong defeated him. Ba Jie joined their group as San Zang's second disciple.
In conclusion, although Ba Jie is a pig-headed, greedy, perverted idiot (as opposed to idiotic pervert XD), he does help out a lot on the journey, albeit reluctantly. He is also one of the most colourful, interesting characters in the story, second only to Wu Kong.