Mrs. Zzyywicz is the mother of Kearney.
She has appeared in some episodes of the series, and was mentioned several times. In "I (Annoyed Grunt)-Bot), Kearney mentioned that she is a stripper. In "Husbands And Knives" it's mentioned that she takes depression medication that makes her bloated. In "Oh Brother Where Bart Thou?", it's mentioned by Kearney that she and her ex-husband met when the prison and the insane asylum had their annual mixer. Given evidence it supports that she was in an insane asylum.