Hydra One of the most hideous creatures of Greek mythology is the nine-headed hydra. For each head that was cut off, the monster grew two new ones.
Hydra is famous for being one of the twelve labors of Hercules.
It was believed that the middle head of Hydra was immortal. When Hercules lopped off a head of the Hydra, two more grew out of the old one. With the help of his servant Iolaus, Hercules managed to burn away the heads of the Hydra and bury the immortal one under a huge rock.