The Cauldron of Life is an ancient mystical artifact, presumably created by human sorcery. As the legend goes, if the stone skin of a gargoyle (along with other ingredients) is boiled in the cauldron for a night and a day, anyone who bathes in the mixture will live "as long as the mountain stones."
The Cauldron somehow came into the possession of David Xanatos, who enacted a plan to kidnap Hudson for two purposes. First, the required stone skin. Second, he planned to use Hudson as a test subject. However, Hudson managed to escape before the second purpose could be accomplished, so Owen volunteered and stuck his left hand into the mixture- whereupon it promptly turned to stone.
Having discovered that the Cauldron was useless to him for immortality, Xanatos melted it down and used it in the construction of Coyote 4.0. The magic in the iron of the cauldron allowed this Coyote to hold and imprison his namesake, Coyote the Trickster. Coyote 4.0 was destroyed, and it is not known what has happened to the metal of the Cauldron.