"Mistake In Gray"

This was strange. I had completed a nice drawing and decided to use the same technique I used on the manatee several days ago. Washed over the entire drawing with soft vine charcoal, then I was going to lift areas for highlights, etc. Well, the entire drawing disappeared. Then, I rubbed over it with a soft cloth and this figure appeared. Looks like a cat with something sticking out of the head - which has nothing at all to do with the original drawing of a hummingbird. Kinda creepy eh.