Have Hydras been created by someone else already?
I've got this idea after all there are no hydras in the encyclopedia however I dunno after all I'm not aware if someone else has already shared their version.
And I've seen a hydra girl before, however no offense (if she was your waifu) but, she looks more like a gorgon to me.(in mythology not all gorgons have medusa's tale.)
Or shall I do something more unexpected?