Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Black stuff floating in mine...

I called my brother who has used this several times since I literally just got it in the mail yesterday....I asked him if it was normal for black stuff to be floating around in the bottle (unopened still)...he said it definitely should not be that way. It really looks like black moldy strands floating around (settled at the bottom unless you shake it). Very very nasty. Probably just a defective bottle, I'll be contacting amazon right now for a refund, but I'm posting this as an attempt to make the manufacturer aware and hopefully prevent other folks from receiving something similar.Contacting amazon now.