Stephen and Martha Thompson are two individuals who have a deformity known as Reverse Polarity Syndrome or Torsonic Polarity Syndrome, TPS for short, which causes their faces to resemble buttocks. The Thompsons met each other at a TPS convention in France. According to them, they still have fully functional face organs, such as mouths, noses, and ears, and contrary to what is said, do not have faces where their buttocks should be. Their son is revealed to be Ben Affleck, who had apparently been missing for over 20 years. Also, according to them, more than 11 people worldwide suffer from Torsonic Polarity Syndrome.
The Thompsons came to South Park from Wisconsin after seeing the photo of Kenny on the milk carton, believing it was their son, Tommy. Mr. and Mrs. Thompson become a minor attraction in South Park for their unusual appearance. Whenever the abnormality is brought up in discussion by the couple in conversation, the others pretend not to notice out of kindness or to prevent embarrassment.
In "Freak Strike," the Thompsons can be seen in the picket line with the other individuals with deformities and in the background of their protest video. In "I'm a Little Bit Country," they make cameos, along with many other minor or one-off characters from previous episodes, during the ending song.
Martha has blonde hair and she wears a pink shirt and blue pants. Stephen is bald and wears a blue shirt with a red tie and gray pants. Both wear black shoes.