Born in 1903, Sandy was kidnapped by Diego Avila and his rogue faction of the Men of Letters in 1925. The terrified Sandy was bound to a table in the Portsmouth, Rhode Island chapter house where Diego performed a ritual to open a rift into another universe. From the rift emerged the tentacles of Yokoth which ensnared Sandy, allowing Yokoth to possess her body, killing Sandy in the process.
In 2018, Yokoth, pretending to be Sandy, was found and released by hunters Sam and Dean Winchester. After Yokoth's true identity was revealed, she told Dean that the real Sandy had been dead for a long time. After Yokoth's failed attempt to bring Glythur into the Main Universe, Glythur dragged Yokoth back to their world, taking Sandy's body with them.