There have long been rumors about enormous crocodiles living in the sewers of Unknown. Those are just that; ridiculous rumors.
What is true, however, unbeknownst to the general public, that in 1967, an alien probe tagged a crocodile in the Emerald City Zoo and granted it superhuman strength and -intelligence.
The creature escaped confinement and retreated to the sewers, where it now roams, only known as Gator.
Efforts by Unknown to capture it have continuously proven unsuccessful.