Great Devourer

The Great Devourer is the true main antagonist of the second series of Lego Ninjago. His venom is why Lord Garmadon is evil. He is released by Pythor and began attacking Ninjago until the Ninjas get him to attack his own tail, allowing Garmadon to destroy the beast with the four golden weapons.

Description
The Great Devourer is a massive green snake with frills on the back of its head that is worshipped by the Serpentine as a god. If the creature is allowed to eat, it grows in size; in other words, the more it eats, the bigger it gets.