Clear / white, edible substance that turns red in presence of saliva?
I want to make "glass" potato chips for Halloween. I think it would be fabulous to add some sort of coating that could create "blood" when people eat it for an extra horrifying bonus. I seem to remember some candies that did this, but can't remember what. Anyone have any idea how to accomplish this? I don't know enough chemistry to figure this out and can't seem to get a good answer out of Google.