A game I can't die at animal crossing

So again our oldest boy wakes up early. He had an accident. So I get him cleaned up, change his bedding and make him a snack. Once again we end up on the couch and I'm watching him play his switch.

After a few minutes he says Daddy I made you an island and I promise you can't die.

So I'm not really sure what I'm doing or why I have to put grass, bugs, fruit, shells and other things in my pocket. But he's right I haven't died yet but I did get stung by a bee a few times.