Oolong is also a character from Akira Toriyama's anime series, Dragonball. For Americans, Oolong appears in the TV series Dragonball Z, but he plays a very minor role.
Oolong was originally discovered early in the Dragonball series by Goku and Bulma. A lazy shapeshifter, Oolong was terrorizing the citizens of a town by appearing as a demon. The catch is that he can only remain shape-changed for a few minutes, since he was kicked out of "shapeshifter school" (as Yamcha's shapeshifting companion Puar tells us). After "saving" the village from the demon and finding out what Oolong really was, Bulma forces the pig to travel with them, much to his discontent.
As far as I know, the only thing this character does in Dragonball Z is try to look up girls' skirts (though Cartoon Network omits most of those parts) and worry about how the next world disaster is going to affect him.
Note: because of poor translation
, Oolong may appear as Oorong, Oulong, or Ourong. Most of the subtitles I've seen use Oolong, as do the English dubs.