Catti, the younger sister of Catty, is a monster who resembles an anthropomorphic cat. She has black hair, white fur, and black makeup on her eyes, a pink stripe in her hair, and pink shoes. She speaks in a monosyllabic, unresponsive manner, tapping and clicking on her phone and then providing vague, nondescript answers. She sits in the leftmost column in Alphys's class, with Noelle in front of her, Jockington behind, and an empty seat to her right.