Nina Skalka is just a small background character. She has only had one speaking role, in Milhouse Doesn’t Live Here Anymore, where Milhouse insults Mrs. Krabappel on the school bus. She applauds him along with the school bullies, implying that she herself is one. She is blonde, wears pigtails, and wears pink. She is usually seen in Bart’s class and her name was only mentioned once by Mrs. Krabappel