It is said about Hydra
" Hydra the nine-headed water serpent, off-spring of Typhoon and chidna,
lived deep down in the swamp and killed with the poison-like breath As one
head was cut off by enemies, two new heads re-appeared It was Hercules to
kill Hydra by burning her neck after decapitate each head and trapping her
body under a huge rock, Where it's still buried until this day "