Is there such a thing????
Suzy

I've heard of various colors, typically blue, but I've never heard of black -- not to say they don't exist, I've just never heard of it.
I'm wondering if what you are seeing may be some sort of shadow? A lot of folks have reported seeing black, or dark shadows in shapeless forms, large and small, in association with paranormal activity.
Have you gotten these on film?

Yes it is on film. Someone took a picture of the basement curtain and it's on there. I have two pics of the curtain, one with the spot and one without.
Suzy

Here are Suzy's pics:

Black Orb?


Another view of the same area