in the Cartman v. Broflovski ballsucking case...
The episode begins with Cartman directing the other boys through a forest in search of a leprechaun. A skeptical Kyle makes a bet that if Cartman can prove leprechauns exist, Kyle will suck Cartman's balls, but if not, Cartman will owe Kyle $10. To Kyle's shock, they find a leprechaun and chase after it. They eventually catch it in a trap.
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When Kyle argues that leprechauns are just imaginary, the man tells him that just because something is imaginary does not mean it is not real.
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... Cartman, angry that Kyle has refused to fulfill his part of their agreement, takes Kyle to court, where the judge sees the contract Kyle signed and orders Kyle to suck Cartman's balls within twenty-four hours or he will be arrested.
https://en.wikipedia.org/wiki/Imaginationland_Episode_I
"This is a victory for the justice system..."
Legal pundits discuss the state court case stemming from Cartman and Kyle's bet, Cartman v. Broflovski which ruled that imaginary characters are indeed real...
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The Supreme Court overturns the "Cartman vs. Broflovski decision" that imaginary creatures are real imaginary creatures are declared not really real, so the government can bomb Imaginationland. Kyle is no longer legally required to suck Cartman's testicles, and he is instructed by Stan to stall the launch.
Kyle and Cartman break into the Pentagon again and Kyle, who finally agrees with him and convinces the officials to not bomb Imaginationland by arguing that imaginary creatures are just as real as real people because of the impact they have on people's lives. Cartman responds by telling Kyle that since imaginary creatures are real after all, then he loses their bet, and still has to suck Cartman's testicles. Kyle finally snaps and berates Cartman for not caring about the danger Stan and Butters are in just because of a stupid bet and that he doesn't care who won, because Kyle would rather go to jail than humiliate himself by sucking Cartman's testicles.
https://en.wikipedia.org/wiki/Imaginationland_Episode_III
"Whatever you imagine to be real, is real."