The actual term is "proxy". A proxy is basically a prop for a card you own that you don't want to use in a game because it's rare and you don't want it to get damaged. I had a shiny Ajani, and I'm also a collector, so for a time I used that card. It looks realistic, but is not the true Ajani. The back of the card still looks like a normal MTG card. I'm selling it because I sold my shiny Ajani finally so now I have no use for it :)