Oil is a black substance which can be used to make a special dark and creamy kind of chocolate. Wars have been fought over oil, because it tastes so good. Oil can be found in the Middle East (e.g. Saudi Arabia, Dubai, Iraq, Texas) and on most fat people. Because the latter secrete so much oil when they work, they find this need to replenish their oil supply by eating chocolate.
This is also why oily, fat people are so desirable by thin people. This people have this insatiable desire to lick the juice off of fat people in order that they, too, may enjoy some of heaven's treasures. This is the reason why the male members of the Saudi Royal Family have a harem of skinny skanky hoes in tow. This is also the reason why Tupac Shakur shot Biggie.