I looked at the canon Pariah Dark and realized that something was wrong. The most stereotypical villain? Well, noooo.
(In any case, ghosts are made up of ectoplasm. They can probably change how they want. It's not a genderswap, it's just thin. And long. Like super-tall, haha. Inhumanly tall. Anything about how the Crown drained most of his powers, he deflated, and now he's stuck in the human world with his heir looking after him? Heh.)
It's just the perfect material to cause an aneurysm in a family of bats.
So, the tired Bitburger worker who served them decided that it was probably time for her to quit after all