She is an assistant kindergarten teacher who works for Mrs. Thistletwat. She would like to open a school for monsters someday though. Even though she's performed by D'Abruzzo in the original Broadway show, the character's voice sounds like that of Prairie Dawn, who is performed by Fran Brill. Kate Monster is in love with Princeton. In the show they have a fight, so Princeton suggests that they should just be friends. While Lucy T. Slut is in a coma, Princeton and Kate try to patch things up. The Kate Monster performer also performs Lucy T. Slut.