Shoggoth

The Shoggoths were "protoplasmic masses capable of taking on any form". (PROSE: The Taking of Planet 5) They were the servitors (PROSE: The Taking of Planet 5, White Darkness) of the Elder Things, (PROSE: The Taking of Planet 5) or Star People, (PROSE: White Darkness) an advanced civilisation who lived on Earth millions of years before humanity. (PROSE: The Taking of Planet 5, White Darkness)

According to an account which depicted these events as real hitory, the "engineered slave-caste" eventually rebelled against their creators, becoming the voracious rulers of vast wastelands between increasingly depopulated cities. Eventually, the Star People began returning to the stars, leaving the servitors behind. Around the same time, the last of the Great Ones, another powerful alien race who had settled on Earth, went underground due to attack by decay-spreading predators. (PROSE: White Darkness)

However, other accounts depicted the shoggoths and Elder Things as elements of At the Mountains of Madness, a purely fictional work by H. P. Lovecraft. (PROSE: The Taking of Planet 5, White Darkness)

The Sixth Doctor and Flip Jackson encountered a version of the shoggoths created by the Somnifax within Lovecraft's mind. (AUDIO: The Lovecraft Invasion)

During the War in Heaven, a Celestis fictional generator brought a version of the Elder Things' Antarctic city into existence as described in the novel, complete with shoggoths. (PROSE: The Taking of Planet 5)