Blueberries Black Stool I Know That Black Stool Is Bad, But What About This?

I know that black stool is bad, but what about this? - blueberries black stool

My chair looked like a sand ... some light on the skin, unusual ... but there were small patches of this stool, dark gray. Is it bad chair? Or is it normal? I ate pizza last night, took the sofa oral codeine syrup prescribed for me for my .. I had this cough and thats jus a new promegranate mixture of juice and cranberry juice. After I relieved myself from the stool ... My "out" very badly stung, as if he had diarrhea ... but it was a solid .... normal stool What is wrong?