This is a Pokemon XY Black Star Promo Mew EX XY126 Full Art card.

Front surface is fine. Back has noticeable whitening on all four corners and edges. There is also a medium crease on the top right corner (as viewed from the back). Very beaten up but structurally still fine.

Protected in a penny sleeve + top loader + team bag, plus in between two pieces of carboard and a bubble mailer. Shipped with USPS Ground Advantage. Feel free to ask for more photos!