Sack of Sacks

Inside this hand-sized sack is a Medium-sized sack. There is no room to store anything inside the original sack. When you pull a sack out, roll 1d20 and add 1 for each sack pulled out in the last 24 hours. On a result of 20 or higher the hand-sized sack is empty and it becomes a mundane item. Otherwise there is another Medium-sized sack inside.