The Japanese text is an insult. Anyway, it's really lame. It looks like an apple in your pocket or in your house, but like a leaf out on the ground. It occurs when you hack your money. The max you can have in your wallet is supposed to never exceed 99k bells... same as a bag of bells. SO when you click on the money in your wallet, one of the options is to remove all the money there (placing it in a bag)
When you hack your money, it says you have 999,999,999 bells in your pocket. When you click the wallet and tell it to remove all the money, instead of creating a 999m bag, it creates the Japple.
Lame
Lame
Lame