Stan's Uncle Jimbo and his war buddy Ned take Stan, Kenny, Kyle and Cartman on a hunting trip in the mountains. When they arrive in the wilderness (just outside of South Park), Jimbo gives each of the boys a gun, a can of beer, and a pack of cigarettes, and the hunting festivities begin.
It soon becomes apparent that Jimbo and Ned's idea of hunting is to slaughter every living thing in sight via military weaponry, regardless of the regulations, which they get around by yelling "It's coming right for us!" in order to exploit the loophole that they can kill any animal in self-defense. Stan proves to not have the proper temperament to enjoy hunting (or at least Jimbo and Ned's idea of hunting), and finds himself unable to shoot a living target even when provided the opportunity. However, Jimbo appears impressed with Kenny, who drinks gasoline straight from the can. While hunting, the boys realize that one of the nearby mountains is rumbling, a fact Ned and Jimbo ignore until it is too late.
Meanwhile, on the mountain, Jimbo accidentally sets Ned on fire while the boys are roasting hot dogs, and Cartman tells the story of Scuzzlebutt. Cartman describes Scuzzlebutt as a creature that lives on the mountain and kills anyone who dares to climb to the top because it likes the taste of blood and to add pieces to its deformed body. Instead of a left hand he has a piece of celery and one of his legs is missing and has been replaced with Patrick Duffy. He also claims that he weaves wicker baskets as a hobby.
The boys don't believe Cartman's tale, so he decides to dress up as the creature the next morning in order to scare them. His plan backfires, however, when the boys tell Jimbo and Ned that Cartman is missing. Once Cartman dressed up as Scuzzlebutt is found, they realize they could become famous by shooting Scuzzlebutt. They start shooting at and chasing after him until Cartman reveals that he isn't Scuzzlebutt, bringing disappointment to Ned and Jim.
At a lower elevation, some of the townspeople are organizing a search and rescue mission for the hunting party (yet unaware that the mountain is a volcano and about to erupt) while other South Park residents dig a trench, under the guidance of Randy, to divert the lava away from the town. Suddenly, the mountain erupts, and the hunting group tries to flee only to find themselves trapped on the other side of the trench.
The real Scuzzlebutt then appears and weaves a wicker basket, carrying the hunting party to safety. The lava then flows through the trench and, due to Randy's miscalculation, destroys Denver. Stan then kills Scuzzlebutt in a misguided attempt to prove he can kill something and make Uncle Jimbo proud. Unfortunately, Jimbo is less than impressed, saying the "some things you do kill and some you don't." Stan doesn't understand, since earlier in the episode, Jimbo would have shot an endangered species. The boys finally decide that hunting sucks and go to watch cartoons.
"Volcano" had originally aired on Comedy Central in the United States on August 20th, 1997. Similar, to the early South Park episodes before it, was slightly watched by more than one million viewers, according Nielsen ratings. This was considered high for a cable program in the United States at the time. The Environmental Media Association nominated for the episode for an Environmental Media Award in the "TV episodic Comedy category. However, the eventual recipient of the award was The Simpsons for the episode named "The Old Man and the Lisa.
"Volcano" generally received positive reviews. USA Today critic Matt Roush praised this episode, including the "Duck and Cover" films. The Advertiser called this episode "outrageously lewd" and "hysterically funny". The Washington Post critic Tom Shales consider episode funnier than its precedent. Peter Hawes of The Sunday Star-Times in Auckland, New Zealand stated that the episode was funny and intelligent. He stated "Once again, the US national psyche is imperishably captured by a crude cartoon". He liked the way adults were portrayed as less sensible than children, and he particularly enjoyed the "Duck and Cover" videos: "It is terrifyingly funny, for it is a word-for-word recreation of the insane Atom-bomb Safety film, created and distributed in 1952 by the US government, who never for a second thought it would work". The Daily Record of |Glasgow, Scotland praised the episode and described it as "hardcore humor". "Love it or loathe it, you can't ignore the adult animation series whose bite is worse than its bark".