Item from A Court of Thorns and Roses by Sarah J. Maas
A primordial artifact of creation — the object from which all life in the world was made, now a weapon capable of unmaking the Wall and reforging mortals into Fae.
The Cauldron is older than the Fae, older than the world as anyone knows it. It's a massive iron vessel, unadorned, and radiating a power that makes even High Lords instinctive step back. It was used to create the world — to pour out life, land, and sea — and it can unmake anything it made. The King of Hybern possesses it and has already demonstrated its ability to shatter wards, transform mortals into High Fae against their will (as happened to Nesta and Elain), and potentially destroy the Wall entirely. It's not sentient exactly, but it has a will — a pull that draws certain people toward it and rejects others. Nesta stole something from it during her forced transformation, and the Cauldron wants it back. It is the story's central MacGuffin: whoever controls the Cauldron controls the shape of the world.
Also known as: the Cauldron, the great Cauldron