She was portrayed by Cloris Leachman.
Ida hasn't changed much over the years and in a display of almost undeniable evil she went as far as drugging a wealthy chinese man in order to effectively force him into marrying her - making him happy around everyone, even the unpleasant Ida. She also began drugging Malcolm's entire family (even baby Jamie) when they tried to stop her scheme but this proved to be her scheme's undoing because she used all the drugs on them, the chinese man came out of it just in time and ran off.
She does however have some love for her family. Ida has saved Dewey's life once in the past, which cost her her leg, (Hal has told Dewey it's her only chance to get into heaven) and is also openly affectionate towards Reese due to him being the "strong" one and also the one that doesn't question her authority - she dislikes Malcolm because he is neither strong nor does he tolerate her abusive behavior. Also, according to Francis, she's threatend by anyone with an ounce of ambition, which may explain her hatred of Malcolm.
She is so horrible that whenever she appears, the family is forced to stop fighting and form a truce to get rid of her.