In the Cthulhu Mythos, Shub-Niggurath is an Outer God. Shub-Niggurath is usually portrayed as female and one of her most common epithets is, "The Black Goat Of The Woods With A Thousand Young".
Appearance: Lovecraft originally described Shub-Niggurath as an "evil black cloud". However, with the growth of the Cthulhu Mythos and of the added works of other mythos-inspired authors, Shub-Niggurath has grown to become perceived as a gigantic, black hovering mass of fleshy tentacles, mouths, eyes, and goat legs.
Lore: Shub-Niggurath is the inspiration behind the worship of all mother goddesses of old. Shub-Niggurath is worshipped as a god by several species of intelligent life in the universe, including humans and Mi-Go.
Shub-Niggurath has multitudes of offspring which appear somewhat like trees with goat hooves. Such monstrosities are said to dwell in forests and wooded areas.
There is some confusion between Shub-Niggurath and "The Black Goat". It is possible that the two are separate entities, or even that "The Black Goat" is an avatar of Shub-Niggurath.
Powers: Shub-Niggurath can grant immortality to her worshippers in a special ritual in which the human is ingested and then later excreted as a changed being, somewhat satyr-like in appearance.
Defense Against Shub-Niggurath: Practically none, save the Elder Sign which repels her.