|The Seer's Prenatal Tonic|
The Seer's blood
The Seer's Prenatal Tonic was a potion brewed by the Seer to strenghten the unborn child of Phoebe Halliwell and Cole Turner, who was possessed by the essence of the Source of All Evil. It was designed to increase the evil side of the child while eating away at the good in Phoebe.
The Seer began giving the tonic to Phoebe after Cole was crowned as the Source and she became the Queen of the Underworld. However, Phoebe hated the taste of the tonic and eventually poured one glass into a potted plant. When the plant withered and died, the Seer admitted the true purpose of the tonic.
When Phoebe confronted Cole, he revealed that he had ordered the Seer to give her the tonic, claiming that he wanted to spare her the pain of the inner struggle between good and evil. The fact that she stopped drinking the tonic eventually contributed to Phoebe choosing to rejoin her sisters and vanquish Cole.
Fearing that the Seer was still after Phoebe's baby, Phoebe mentions that the tonic the Seer fed her with was made with her blood, meaning they could use it to vanquish the demon. They arrive at the penthouse to find the tonic, only to walk into a trap set by the Seer, and Phoebe tears off her earring to save herself and collect a sample for the vanquishing potion.