Talking on the phone

I just ran into the post office to pick up our mail and when I came back to the car I could hear hunter talking to someone. I could not figure out who he was talking to because it sounded as though he was having a conversation. When I look back I saw he was using his rock phone to make a call. When I asked we was talking to he said he was talking to Michael who works at the plumbing store. Hunter also wanted me to add that Michael is invisible because he is his invisible friend.