Just when I thought Matt & Trey couldn't be more tasteless and offensive, they go and prove me wrong.
In "Tonsil Trouble" (episode 1201), Cartman needs to have his tonsils removed. After he wakes up the doctor informs him that he contracted HIV from a blood transfusion.
Since Cartman is the ultimate dick, Kyle can't help but laugh at his predicament, which pisses Cartman off. To teach Kyle that AIDS isn't something to laugh at, he sneaks into Kyle's room in the middle of the night and injects him with his infected blood.
Kyle gets sick and goes to the doctor who runs a battery of tests and discovers he has HIV. Kyle knows how he got it, and he and Cartman get into a fight. Kyle begins breaking all of Cartman's toys, and just as he is about to break the Xbox, Cartman tells him that he has a plan.
Cartman and Kyle fly to Los Angeles to see Magic Johnson, who has had the virus for fifty years and is still alive. Magic Johnson tells them he doesn't know why he is so healthy, but Kyle suspects it has to do with something unusual in the environment that Magic is exposed to that other people aren't.
Magic leads them on a tour of his mansion and everything looks ordinary enough, then they get to his bedroom, which is piled high with cash (Magic doesn't trust banks).
They go to an AIDS research laboratory and explain their theory to the scientists. One scientist puts a slide of HIV-infected blood under a microscope, waves some cash at it, and the HIV particles detach from the T-cells and retreat screaming in horror.
Unfortunately, waving cash at HIV only causes it to retreat temporarily. So they hypothesize that if waving cash at HIV scares it, that maybe injecting cash directly into the blood will kill it.
The scientists take a million dollars in cash and place it in an apparatus which grinds it up and distills it down into a syringe of serum which they inject into Kyle. Sure enough, the million-dollar serum cured AIDS completely.
The show ends with excited health officials going to Africa to tell AIDS-infected Nigerians that all they need to do is inject all their cash into their bloodstreams, and then an awareness benefit concert featuring Jimmy Buffet singing a song about AIDS to the tune of "Margaritaville." The End.