The Hydra was a
many headed snake. It lived in Argolis near Lake Lerna. One of
the heads was immortal, and the rest would grow back when they
were cut off.
One of Hercules'
labors was to kill the Hydra. When he found it, he cut off one
of its heads with his sword. Immediately, two more grew back in
its place. Hercules then went off and started a fire. He took
a burning limb and cut off a head, and burned the area where it
was cut off. No head grew from the scorched area. He did this
to all of the heads. He buried the immortal head. The rest of
the body died.