The Hydra Dragon
The Hydra Dragon lives in water. It has many heads and when one head is cut off another one or two heads grow back. It has venomous breath, blood and fangs. It has one head that will not die when it is cut off, some people think this head was made of gold.
There was a hydra dragon called Lernaean that was killed by Heracles. Heracles dipped his arrows in the venomous blood of Lernaean and used this to kill his enemies.