The Hydra is surely a strange underwater creature. Though this one is a freshwater invertebrate, it can pretty much regenerate itself if chopped into little pieces. So, really, you can never get rid of it. You’re caught in a swordfight with a Hydra, you slash him to bits, thinking, “Mwahahahah! Victory at last!” You were so very wrong. Not only have you not killed him, but you’ve created a hundred little mini Hydras that’ll just pop up and chop you to pieces. Doesn’t this remind of you of Mickey and the magical broom? Maybe they got that idea from this little creature. (It’s a good thing they’re tiny little buggers.)
And maybe you didn’t win the battle at all. Maybe he used his little tentacles and shocked you with his mighty sting. Oh yes, regrowth, magical stinging powers and is asexual? You’d think he was out of this world!