The Vulcanos

Stan's uncle Jimbo and his friend Ned take Stan, Kenny, Kyle, and Cartman on a hunting trip in the mountains, but Stan is unable to shoot a living target. Cartman tells the story of Scuzzlebutt, a mutant creature, and decides to dress up as the creature to scare the others. But in doing so, Cartman almost gets shot. Back in town, geologist Randy Marsh discovers that the mountain is a volcano that is about to erupt, and the townsfolk dig a trench to try to divert the lava. The mountain erupts and the hunting group find themselves trapped. The real Scuzzlebutt then appears and carries the hunting party to safety. Stan kills him to make Jimbo proud as the lava is diverted onto Denver city.

Ian Norville, an autistic boy, goes missing while on a school trip to the Natural History Museum. Jack instantly suspects Ian's father, Daniel, after he exhibits some odd behavior immediately following the disappearance. It is speculated that after some recent revelations in the Norville family, Daniel may be relieved that Ian is missing, and perhaps even personally involved in the disappearance. As the team investigate further, they suspect that various people close to Ian could be involved. They also learn how difficult it is to raise a disabled child, both for the family, and the child itself.