The odyssey of Eric Cartman's true lineage was a huge mystery in South Park's first season. It got to the point where a search for Cartman's father took place in Season 1, Episode 13, "Cartman's Mom is a Dirty Slut," leading to Dr. Mephisto doing a DNA test. It was a necessary test -- because almost any man in town could have been Cartman's father, including the roster of the 1989 Denver Broncos.

That episode ended on a cliffhanger with the series promising to announce the truth four weeks later at the start of South Park Season 2. But when Season 2 debuted a few weeks later, it wasn't the episode that fans were expecting. Instead of learning who fathered wannabe authority figure Cartman, viewers received an epic April Fools' joke featuring Terrance and Phillip.

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How South Park's April Fools Fakeout Played On Viewers' Expectations

An angry Terrance and Phillip hold boxes in South Park

Rather than finding out who Cartman's father was, South Park gave its fans a standalone episode featuring two supporting characters. Viewers who tuned in to the Season 2 premiere were greeted with a title card announcing an episode called "Terrance and Phillip in Not Without My Anus." It focused entirely on the Canadian duo as they attempted to free Canada from Saddam Hussein.

Terrance and Phillip had previously been introduced as the stars of an in-universe TV show that South Park's kids loved. However, this was the first time an episode had been entirely devoted to them. In addition to being hilarious, the episode also laid the groundwork for the show's absurd yet brilliant interpretation of Canada. This would become a key running gag throughout the series; Matt Stone and Trey Parker would skewer TV sitcom factory Canada on many other occasions, including in the feature film South Park: Bigger, Longer and Uncut.

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Who Is Eric Cartman's Father in South Park?

"Terrance and Phillip in Not Without My Anus" closed with the announcement that it would be several more weeks before the next Season 2 episode, making fans wait even longer to resolve the mystery of Cartman's father. The series had already proven to be daring throughout its first season. But the Terrance and Phillip fakeout showcased that Stone and Parker weren't afraid to mess with their fans just as much as South Park lampooned celebrities like Kanye West.

Season 2, Episode 2, "Cartman's Mom is Still a Dirty Slut" declared that Cartman's put-upon mother Liane was a hermaphrodite and therefore also his father. However, that was debunked in Season 14 when the town admitted lying to Cartman in order to preserve the Broncos' winning season. Season 14, Episode 6, "201" finally revealed Jack Tenorman to be Cartman's father. However, the Season 2 premiere remains a classic episode. It showcased South Park's ability to subvert expectations and is still one of the long-running show's biggest surprises.

South Park airs Wednesdays at 10:00 p.m. on Comedy Central.