Oldsmobile is a short-form of the term Old Smo's Bile, referring to the bile of legendary pipe-swallower, Smokey McAndrews.
This unusual term is used as a metaphor for an unlikely turn of events. The adoption of this term into common use was the inspiration for the name of a vehicle that is able to make unlikely turns.
The Diamond Steer
On September 3, 1990, during a practice-run of his performance where Old Smo was swallowing a rather thick PCP Pipe, a sudden urge to sneeze resulted in a rather disturbing bodily reaction where bile spewed from the end of the pipe -- landing on a near-by cow. The cow reacted quickly, running off wildly, knocking over stage equipment and loudly sounding its displeasure. This sound was misinterpreted by a nearby steer (part of the same act), who, although castrated, was somehow attracted by the then-enraged cow. Before it could reach the cow, however, the steer passed out from a heart-attack, and died. Although seemingly an unfortunate event, it was later discovered that the steer had previously swallowed several diamond rings, resulting in a windfall for its owner.
Oddly enough, that was not the last time "Old Smo's Bile" had resulted in unlikely luck for others.
The Winning Stub
A similar incident occurred during a side freak-show that Old Smo had been performing in at a horse-race in New York state in October 1991. This time, he was swallowing the longest tobacco pipe known to man, and had an unfortunate allergic reaction to the tobacco taste. In this case, his bile landed on a winning betting stub lying on the ground, unclaimed. The bile-coated stub was used to garner Old Smo a crisp five-dollar bill, and a parking validation (for his Oldsmobile!).