What is bad JuJu?

What is bad JuJu?

Running into a Jackalope is bad JuJu. (Fear them!).

There are some real Jackalopes, infected by the Shope papillomavirus. ("Shope papillomavirus provided the first mammalian model of a cancer caused by a virus")

Maybe this is the same thing that that guy from Indonesia had... (Well, they were both papilloma viruses).