Originating from Greek and Roman mythology, what serpentine water monster was believed to dwell in the lake of Lerna in the Argolid?

The Hydra, also known as the Lernaean Hydra or Hydra of Lerna, is a snake-like water monster from Greek and Roman mythology said to reside in the lake of Lerna in the Argolid. This lake was widely believed to be a portal to the underworld, but in the popular Hydra myth, Hercules slays the monster.

Asked by Rachel Bortles · Last updated 4 years ago · 4.5K views · SOURCE