This is what you say/scream when you see someone wearing shoes or other footwear that are dirty and/or non-brand unknown. You should also point your finger in the air then while saying "what are those?!" Make your way down to the person shoes, all while their back is turned.
*boy sees dirty non-branded shoes*
Boy: What Are Those?!
Person with ugly shoes: huh? (Unaware of what just happened, so they laugh)