The Last Temptation of Krust - S9-E15
Hank WIlliams, Jr.: ♪Can you name the truck with four-wheel drive? Smells like a steak and seats thirty-five. Canyonero. Canyonero. Well, it goes real slow with the hammer down. It's the country-fried truck endorsed by a clown. Canyonero. Canyonero.
Krusty: Hey hey!
Announcer: The Federal Highway Commission has ruled the Canyonero unsafe for highway or city driving.
Hank Williams, Jr.: ♪Twelve yards long, two lanes wide, 65 tons of American pride. Canyonero. Canyonero. Top of the line in utility sports. Unexplained fires are a matter for the courts. Canyonero. Canyonero. She blinds everybody with her super high beams. She's a squirrel-squashin', deer-smackin', drivin' machine. Canyonero. Canyonero. Ya! Ya Canyonero! Whoa Canyonero! Whoa!
Answer: I'm not sure if this is the one you're thinking of, but an episode of "Ray Bradbury Theatre," called "A Sound of Thunder," dealt with a similar matter: a group of hunters travel back in time to hunt dinosaurs, only to find things have changed when they get back because someone stepped on a butterfly.
Xofer