In Greek mythology the Hydra (or Lernaean hydra) was a serpent-like monster. According to Theogony 313, the Hydra is the child of Typhon and Echidna. The Hydra had many heads. If you cut off one hydra head, two more would grow back in its place. It is also said that the Hydra's teeth were able to raise skeletons from the dead. There are pictures of the Hydra on vases and bronze plates dating back as far as the 7th century BC.