The Elder Things (also "Old Ones") were the first race to descend from the stars and raise great cities on a young Earth, hundreds of millions of years ago. They have barrel-shaped bodies, five-pointed starfish heads, five eyes, and membranous folding wings, and combine plant and animal traits, able to subsist on light or nutrients alone.
They bred the formless protoplasmic Shoggoths as living labor, and it is implied that all life on Earth descends from their experiments or refuse. Their civilization declined through wars with the Mi-go and the eventual revolt of the now self-aware Shoggoths, leaving their last city buried beneath the Antarctic ice.
In "At the Mountains of Madness," the expedition reads the city's bas-reliefs and grasps both the origin of Earthly life and humanity's insignificance. Yet the Elder Things are not simple villains — as the narrator laments, "They were men!" — and become objects of pity for a fallen civilization rather than mere monsters.