Hydra

Hydra (1)

In Greek mythology, Hydra was a many-headed water serpent that was killed by Heracles. [Lernaean Hydra, Wikipedia]

Hydra (2)

A mother goddess of the Deep Ones, spouse of Dagon. The Esoteric Order of Dagon preached that the children of human/Deep One liaisons would never die, but go back to Mother Hydra and Father Dagon, whom we all came from once. [HPL Innsmouth (online text)]

Hydra (3)

A being that originated in the gulfs Outside. It is, after a fashion, a vampiric entity, living not on the blood of its victims but on their heads—their brains. Through the eons this entity has ravened in the abyss beyond our dimension, sending out its call to claim victims where it could. For this entity, by absorbing the heads and brains of intelligent creatures both of this world and of other planets, emerges with its powers and vitality greatly augmented. The myths of Hydra (1) and Magna Mater are inspired by this being.

The pamphlet On the Sending Out of the Soul is a ruse for capturing victims for the Hydra. The pamphlet explains how to send one's astral self to visit the person of your choice. However, the true effect of the process is to open a gateway and prepare a sacrifice for the Hydra. The person whom you try to visit ends up becoming the sacrifice; the person's head is severed and added to the Hydra's collection of living, anguished heads bobbing on a sea of grey slimy liquid. Paul Edmond used this method to visit Kenneth Scott, thus accidentally adding Scott's head to the Hydra's collection. [HK Hydra (online text)]

Aka: Gorgo; Magna Mater; Mormo.

Hydra (4)

A constellation [Hydra (Constellation), Wikipedia].

Walter Gilman felt drawn to a spot in the sky between Hydra and Argo Navis [HPL WitchHouse (online text)].