Terrence Mephesto
| Gender | Male |
| Age | 10 |
| Hair Color | Dark Brown |
| Occupation | Student |
| Grade | 4th Grade |
| Religion | Roman Catholic |
| Father | Dr. Alphonse Mephesto |
| Mother | Unknown |
| Brother (adopted) | Kevin Mephesto |
| Voiced by | Matt Stone |
| First Appearance | An Elephant Makes Love to a Pig |
About
Terrence is an arrogant, spiteful boy at South Park Elementary who takes pride in his intellect and scientific achievement, but believes many of the other students to be below him as a result. He is far more concerned about science than human safety. He was a rival of the boys who participated against them in the South Park Elementary Science Fair early in the third grade, working with Bill Allen and Fosse McDonald to clone a human. He and his father successfully engineered a human foot and later Evil Clone Stan who Terrence arrogantly freed despite his father's wishes. The clone rampaged across the town before his father killed it. Since his failed attempt against the boys, Terrence has largely receded to the background, though he does make prominent cameo appearances from time-to-time.
Featured Episode
- An Elephant Makes Love to a Pig (s01e05)
- Raisins (s07e14; cameo)
- Breast Cancer Show Ever (s12e09; cameo)