Sherri and Terri Mackleberry are a pair of identical twin students of Springfield Elementary School. Terri is younger than her sister by two seconds. They are in the same class as Bart, by Edna Krabbapel. They are a little bit strange and sometimes they speak in their own language. They will also not hesitate to berate Bart as seen in various episodes.
No one knows whether one twin is Terri or Sherri. However they are really triplets and the third one is out for revenge. According to Episode 13 in Season 22. Sherri and Terri have long, purple hair and always wear the same clothes.