Tony Toponi is the tetartagonist from the American Tailfranchise. He is the one who calls Fievel "Philly". Though he is a male, he is voiced by a female actor, Pat Musick. This is similar to Nancy Cartwright playing Bart Simpson.
In the song "There Are No Cats In America", it is suggested that he is possibly related to the large Sicilian mouse that sings the second verse, as they are both of Itailian decesnt.