The Lernaean Hydra is a creature from Greek mythology, known for its many heads and regenerative abilities. According to the myth, it lived in the swamp of Lerna and was slain by the hero Heracles (Hercules) as part of his Twelve Labors. Each time one of its heads was cut off, two more would grow back, making it a formidable foe. Ultimately, Heracles defeated the Hydra with the help of his nephew Iolaus, who cauterized the neck stumps to prevent regeneration.