Bests & Worsts Reviews from Amazon

Got this set of two stainless steel bowls over a month. Hand wash them with soap n water before and after use. Dry with cloth. Just so happen today I dry the bowl with paper towel instead. And this is what happened?? Use other stainless steel bowls before for previous pets. Never seen this happen. Please tell me is this even safe for my pup to consume water and food from it?? I can only imagine how much of these black metal oxidation he consumed. Yuck!!!!!!