<human>:  Why does the Phantom have a mask in the musical ‘The Phantom of the Opera’?
<bot>: The Phantom has a mask because he is a phantom, and he is a phantom of the opera. The Phantom is a character from the musical, and he is the title character of the play and the musical. The Phantom is a mysterious character who lives in a gothic opera house, and he is the main antagonist of the play and the musical. The Phantom is a fictional character, but he is inspired by the real life Phantom of the Opera, a French musician named Gaston Leroux.