What is a Hydra?

Hydra ("water serpent") is the name of the Lernaean Hydra, a many-headed serpent in Greek mythology.

a hyda is an water serpent that if you cut off its head than 2 more grow back

A hydra is a multi-headed water serpent, usually has eight heads, that breathes acid or fire or something like that, and if you cut off one of it's heads, two more grow back.

they r scary creatures tht have multiple heads... i once wanted them as a pet :3

A dragon with lots of heads and no wings

a Lernaean Hydra is a Greek sea serpent legend that usually has 9 heads, cut one off and two grow back on. the only way to kill a hydras head is by cutting its head off and burning the tip or freeze it solid like in Percy Jackson and the lightning thief (can't remember how has something to do with the lady with snake hair).:D