Zhu Bajie (豬八戒 aka 豬悟能) is one of the three helpers of Xuan Zang in the classic Chinese novel Journey to the West. He is a terrible monster, part human and part pig, who often gets himself and his companions into trouble by his laziness, his gluttony, and his propensity for lusting after pretty women.
Zhu Bajie was originally a general in Heaven before being banished for his misbehaviour. In some retellings of the story, his banishment is linked to the downfall of the monkey king Sun Wukong, but in the novel it was brought on by a drunken attempt to molest the Goddess of the Moon. In any case, he was exiled from heaven and sent to be reincarnated on earth, where by mishap he was reborn as a pig. After some time, he was recruited by the bodhisattva Guan Yin to join Xuan Zang's pilgrimage and atone for his sins (those that had got him thrown out of heaven, and the many he had racked up since).
At the end of the novel, most of Zhu Bajie's fellow pilgrims achieve enlightenment and become buddhas or arhats, but he does not; although much improved, he is still too much a creature of his base desires. He is instead rewarded for his part in the pilgrimage's success with a job as Cleanser of the Altars and all the leftovers he can eat.
In Dragon Ball and Dragon Ball Z, there is a "pig" which is loosely based on Zhu Bajie — it is greedy, ugly, stupid and it has the shape-changing ability. But unlike Zhu Bajie, it is an omittable character in the animations.