Mother Hydra

Mother Hydra is a gigantic Deep One and alongside her consort Dagon is said to rule over the Lovecraftian race known as the Deep Ones.

There is debate as to whether or not Mother Hydra is a lesser Great Old One or merely a grotesquely mutated Deep One - though the latter seems more likely as she doesn't seem to show much in the way of supernatural power outside her gigantic size and unnaturally long life span.

Mother Hydra also acted as the main antagonist and final boss of the video-game Cthulhu: Dark Corners Of The Earth - somewhat surprisingly her consort Dagon was missing (perhaps to avoid the problem of having to face two Great Old Ones in a single game).