In Greek mythology, the Hydra, born to Echadna and Typhon, was so large and ferocious that it had nine heads, eight of which could be killed, but the ninth, the one standing upright in the middle, was unkillable. Hydra grew up in the swamps of Lena in Argolis and used to crawl to the shore, spoiling crops and endangering livestock. The second task of Hercules, the god of power, was to kill this hydra.