Cough, Cough!

I got this stuff called crazy slime. It is a black slime that you can play with. I was thinking how to use it in a magic show. Here is the result:

Cough it up: "Smoker's cough, sorry... gee all the tar."
Even works as a nonsmoker "Oh boy, passive smoking still does the trick!"

Imagine this as a little funny bit during a health convention. Or during a cigarette routine.