The Giant Snake is the first boss of Wario Land II. It is a large, light green snake.
In Wario Land II[]

Wario standing on the giant snake
Giant Snake is fought in the basement of Wario Castle during Defeat the giant snake, the fifth and final story of the first chapter, One Noisy Morning.
At first, Wario finds the Giant Snake curled up and asleep. Wario can attack the Giant Snake to wake it up and start the boss fight. During the battle, the Giant Snake moves its head from side to side and tries to attack Wario by trying to bite him. Wario can attack the Giant Snake by either jumping on it or by Ground Pounding it. About partway through the battle, after the Giant Snake has taken a few hits, it turns red and moves faster. The Giant Snake is defeated after Wario either jumps onto it six times or Ground Pounds it three times.
If the Giant Snake successfully bites Wario, he gets swallowed whole by it and turns into an egg, which bounces up to the ceiling where it shatters, returning Wario to normal. Wario has to make his way back to the Giant Snake to continue battling it.