Terrance and Phillip are Beavis and Butt-Head in the South Park world.Matt and Trey have said in the past that to them Beavis and Butt-Head were like "the blues.
Some time before "Terrance and Phillip: Behind the Blow" they broke up but they were reunited in that episode.
They apparently are so famous that they have their own line of dolls as seen in "Cow Days".
The fact their career is based on an accidental fart Phillip made on the The Ed Sullivan Show at the age of six, because that was the only part of their act Americans understood, may be saying something about Canadian perceptions of Americans.
The duo popularized a catchphrase in the show-within-a-show, as they would invariably say "You FAH-ted! They are the favorite show of Stan Marsh, Kyle Broflovski, Eric Cartman, and Kenny Mc Cormick as well as most of the South Park children.
"Royal Pudding" establishes that they are both Knights in Canada.
While it can be assumed that Terrance is heterosexual, Phillip's sexual orientation is, as of late, unknown.
In South Park, Terrance and Phillip are the stars of a popular television show.
This show-within-a-show serves an interesting role; the parents of the South Park characters view Terrance and Phillip's obsessive fart gags in much the same way that many parents in the real world view South Park - with considerable contempt.
The pair appear as the stars of The Terrance and Phillip Show.
Phillip (Sir Phillip Niles Argyle of Montréal) has blond hair and a blue shirt with a "P", while Terrance (Sir Terrance Henry Stoot from the "small village" of Toronto) has black hair and wears a red shirt with a "T".
It's the same thing over and over, but it's always good".