Ethel Hallow is Mildred Hubble's acid-tongued rival. In their first year, Ethel takes pleasure in taunting Mildred about her inability to train her cat into riding a broomstick and Mildred responds by turning her into a pig. From then on Mildred and Ethel resent each other and Ethel vows to get Mildred expelled. So far she has been unsuccessful. She and her only friend, Drusilla, are always up to mischief, all the time plotting to get Mildred and her friends into trouble, they don't get caught as often as they'd deserve.