0xFFF1 is Animal Crossing's data value for an empty data slot. Out of all the items in Animal Crossing, I am the most unique. No other item has so much use. Think about it! what if your town had items on every available slot and your entire storage areas were full of items, closet, mail, mail storage, everything. that would be horrible! so much clean up. in fact negative usefulness. I am the only item capable of being useful by being used so much.