Katuali

The katuali or flat-tail sea snake ("Laticauda schistorhyncha") is a species of venomous sea snake in the family Elapidae. The species is found only in the waters of the Pacific Islands nation of Niue. 
Description.
"L. schistorhyncha" grows to a total length (including tail) of up to , and is highly venomous, making it one of the most potentially dangerous creatures on the planet. It has a fin-like tail, helping it to swim better. 
Habitat.
The katuali lives most of its adult life in the sea. 
Reproduction.
During mating, the male katuali wraps itself around the female until she is fertilized. Because the eggs would not survive in water, the female swims into a sea cave to lay the eggs in dry crevices. These eggs take six months to hatch, and then the infant snakes make their way to the ocean.