In the swamps of Lerna in underworld
The Hydra in Greek mythology had nine heads.
Hydra from greek mythology?
the hydra
Hydra was a many headed serpent in Greek mythology
The monster you are referring to is the Hydra. The Hydra is a child of Typhon and Echida.
it was trapped in a cave until Hercules accidentally unleashed it (but it was shortly killed)
Ὕδρα.
It was a hydra.
Hercules killed the Hydra in Greek mythology by cutting off its heads, and then cauterizing the neck stumps to prevent them from growing back.
Greek mythology has no chronology in our sense.
The Lernean Hydra is killed by Heracles in his second of twelve labors. However why the Hydra is killed is never fully explained.
No, the Hydra was not real it was a made up myth to add to the stack of made up myths from Greek Mythology.