The Lady Vampire of the Bay was the disguise of Lefty Callahan in "I Left My Neck in San Francisco", an episode of Scooby-Doo and Scrappy-Doo.
The vampire was very tall; she had long red hair with black streaks. She also wore a long purple cloak over a blue dress. Her resemblance to Daphne Blake caused Shaggy Rogers and Scooby-Doo (in an out-of-character moment) to suspect that Daphne was the vampire.
The vampire was a criminal who was recovering her loot. She also posed as an old lady named Mrs. Cornell.