Hydra of Lerna (mythology)

Hercules and the Hydra
The Lernean Hydra
   In Greek mythology, the Hydra was a fabulous serpent infesting the lake of Lerna in Argolis. It had nine heads. If any one of these was cut off, two grew in its place. The destruction of this monster was one of the twelve labors of Hercules. The term hydraheaded is often applied to an evil which it is difficult to suppress. In zoology, the hydra is a small cylindrical animal of low organism found in cold and fresh waters. One end of the cylinder is attached to a suitable base, the other is surrounded by a whorl of tentacles which waft water containing food into the central cavity.