(Super Snake-Armed Octopus)
Myth Class: Sea Monster
The Lernaean Hydra is a giantic octopus that mimics a snake native to its home. If in serious danger, it'll raise all of it's "heads" out the water, making it look like a twin tailed, six headed, monster of a serpent. The "tounge" and "fangs" of the fake heads are only there to aid the illusion.
If a tentacle gets cut, it can regenerate it in just a minute. Though it can sometimes mess up and this result with the octopus having an extra "head". Some have been reported with three, nine, twenty, or even fifty tentacles!
Like some octopi, the Hydra has a venomus bite. If not treated, anyone who was bit by a Hydra will die within a hour.
One famous account of this creature came from Hercules' Twelve Labors. His second one being to slay a Hydra. He succeeded his task by having his companion cauterize the wounds. This prevents the Hydra to regrow the lost limbs, resulting with the death of the Hydra.