Oolong

Oolong is a shapeshifting humanoid pig, standing about three feet tall with pale pink skin, who tends to dress in trousers, button-down shirts, and suspenders. He was expelled from shapeshifting training for stealing the teacher's underwear and lacks the ability to change his form for more than five minutes at a time without a break. With his shapeshifting, Oolong can look like anything at all. Oolong's initial appearance was as a villain who terrorized a village and kidnapped their young women. Son Goku defeated Oolong and the girls were returned to their village. Bulma decided that he might be useful on her Dragonball quest and persuaded him to join their expedition. Eventually he becomes good friends with Goku and the others, and helps them to find more Dragonballs. He plays a large role in the beginning of Dragon Ball, but by the end of Dragon Ball Z, he just shows up from time to time. His poor shapeshifting skills (and innate cowardice) made him a very weak character that didn't have much to do once the tone was shifted to more serious action. In the anime and several movies, he appears quite often as comic relief. He is loosely based on the character Zhu Bajie from the classic Chinese novel Journey to the West.