The Banshee (Dorenda Moore) was the villainess from "Look Who's Barking," the penultimate episode of Season Three of Charmed.
The Banshee is a ghostly demon who attacks people in grief, and early in the episode, she wielded her demonic shriek at a grieving husband, killing him. The Banshee later set her sights on a young teenage girl, who was in tears calling her mother. However, she was thwarted by Phoebe and Piper, as well as Prue (who morphed into a banshee-hunting dog). During this encounter, the Banshee sensed Phoebe's own grief (over Cole) and lunged after her, but was stopped by Piper. The Banshee resurfaced in the Halliwell house, and was vanquished by Piper, but not before her shriek turned Phoebe into a banshee herself.