The Hydra, an enormous creature which was a serpent with 9 heads, 8 of which were mortal lived in the swamp of Lerna.
Sometimes, Hydra went over to the country destroying the herds and laying waste on the fields.
To stop this from happening again, Hercules decided that he was gonna kill the Hydra.
Hercules and Lolaus, his nephew, sped towards Lerna in a chariot. Once they arrived, Hercules stepped out, firing burning arrows towards the Hydra. The Hydra came forward. Quickly, Hercules held the Hydra tightly, However, the 9 headed serpent wrapped itself around one of his feet.
Hercules began to chop of its head, but every time he did this 2 more grew in its place. An enormous crab came to help the Hydra, but Lolaus came to help, killing the creature with a club. Using a torch, Hercules burnt a portion of the woods, so that the Hydra's head wouldn't grow back.
By burning the woods, he was easily able to defeat the Hydra. After killing the 9 headed serpent, he buried the creature in the ground and rolled a stone over its grave. Dipping his arrows in the Hydra's blood made them poisonous. From then, a wound from Hercules arrows were fatal.