After Phoebe had been left behind by her parents and Trevor, Phoebe decided to go play chess by herself at a park. In the middle of the game (against herself), the chess pieces moved by themselves, and then they stopped moving to wait for Phoebe's turn. Phoebe instantly knew this was a ghost, but she decided to go along with it. Phoebe looked around for a second, then looked back in front of her. The ghost (you!!) had shown itself.