An elephant is used here to symbolize or typify something which is extremely remarkable or exotic.
1994 - Fighting Firearms - These men have all seen the elephant and represent a typical cross-section of the staff in general.
RELATED IDIOMS :
a white elephant
a possession that is useless or troublesome, especially one that is expensive to maintain or difficult to dispose of
In former times, the rare albino elephant was regarded as holy. It was highly prized by the kings of Siam (now Thailand) and its upkeep was extremely expensive. It was apparently the practice for a king of Siam to give one of the elephants to a courtier they disliked. The unfortunate recipient would usually be financially ruined by the attempt to maintain the animal.