The Ghost Witch of Old Salem was the disguise of Arlene Wilcox's twin sister.
She was a pale ghost with long, wild green hair. She wore a purple dress and a matching hat. Battery powered wiring gave her a glow. As she is Arlene's twin, her appearance without her disguise is likely identical to her sister's.
She was jealous, selfish, and greedy; she'd stop at nothing to get the family inheritance for herself.
The Scooby-Doo Show
Appearing on Halloween night, as dictated by legend, she shocked the town with her similarities to Arlene. Convinced the witch had taken possession of Arlene, a mob went out to capture her, but they caught Scooby-Doo instead. Thinking her plan had succeeded, she raced back to the graveyard, where Fred Jones and the others had set a trap.
When the trap caught Shaggy Rogers and Scooby instead, she ran off, but fell into the open grave that was being worked on when she first appeared. When the mob arrived, they realized the truth and relieved Arlene of guilt. She tried to make it look like Arlene had been possessed by their ancestor, Milissa Wilcox (whom had an uncanny resemblance to Arlene), because she hoped to drive her sister out of town and keep the family inheritance for herself. The 'witch' and her partner (who had built the suit) were subsequently arrested.
- For some reason she was never unmasked (or had it wiped off as the case may be). This may be due to the fact that she resembles her sister; her real name was also never revealed.