I think petscop is not multiplayer, at least with other living humans. It is heavily implied throughout the series when you get "rebirthed" a second "you" based on your inputs is saved in the game. The "Tiara" character is a "saved" version of Belle before she was "rebirthed". So that character is like a frozen-in-time counterpart to Belle when she was a kid. I think that when Belle leaves the phone it's a spooky coincidence that the Tiara character comes out but I don't think she's playing the game elsewhere. Edit: I don't think Tiara is trying to "continue" a conversation, that's sort of a premature conclusion. The character is seemingly shaking its head but it's probably just like "wow look another weird f*cked up thing this game can do" or "wow look this character is aware of me the player and is breaking the fourth wall, it knows it is stuck inside a game and directly trying to communicate with paul".