A wave of spontaneous combustion is sweeping through South Park, and the mayor charges Stan's father (a geologist) with finding the cause. After working feverishly on the problem, he finds the answer: people are holding in their farts for so long, they're bursting into flame. A grateful nation loosens its sphincters in relief, but their problems aren't over yet. Meanwhile, the boys crucify Cart...A wave of spontaneous combustion is sweeping through South Park, and the mayor charges Stan's father (a geologist) with finding the cause. After working feverishly on the problem, he finds the answer: people are holding in their farts for so long, they're bursting into flame. A grateful nation loosens its sphincters in relief, but their problems aren't over yet. Meanwhile, the boys crucify Cart...