It was one of the many dangerous abilities demonstrated by the Source's Heir. As with Wyatt and Phoebe, the unborn child's powers first appeared through his mother. Phoebe used this power to vanquish the Tall Man, a demon who was imprisoned many years ago by The Source himself and freed by the Seer to kidnap Phoebe and her child. Nobody had been able to vanquish this demon, so Piper was utterly horrified when Phoebe managed to do so by channeling her unborn child's powers. However, this power was not strong enough to penetrate a shield created by the Power of Three spell.