Serpent
In The Fisherman's Battle, the king and owner of the island takes the form of a serpent to fight another king from an invading island that takes the form of a giant centipede. While being a mighty king, the serpent is no match for the centipede's many legs. After the men help fight off the centipede, the serpent showers the fishermen with gifts.
In Wrestling a Serpent, Tsuneyo the wrestler comes across a serpent that is so big that it reaches opposite sides of a marsh at the same time. The serpent was said to be as strong as sixty men.