Here is probably either a paper cardstock or plastic A4 size sheet holder. You can see the thumb/grip crescent shape there on the edge so that you could pull the papers out of it. Like the other Sega 60th Anniversary team up items, the running classic Sonic sprite is composed of puyos as the pixels. The 'speech bubble shaped' area there gives a really good look at what it would be close up. You can see the 60th logo there in the bottom corner.