I can’t remember if I just imagined this joke-fragment, or heard it somewhere, or what. It’s a great setup but I haven’t the faintest clue how it ends, or if it ever had an ending:
A cowboy goes to the Grand Canyon and decides to go on one of those mule rides that go down a trail into the canyon. When he reaches the mule stables at the head of the trail, the man running the mules says “Sorry, we’re booked solid”. The cowboy points at this one mule that has no rider and asks “What about that one?” “Sorry, we can’t let anyone ride him- he bucked a rider into the canyon last month”. The cowboy replies “Mister, I’m the Texas State Rodeo Champ three years running. There’s nothin’ on four legs that can buck me off!” So the mule runner says “Fine, have it your way” and lets the cowboy take that mule.
So they take off down the trail and when they’re about halfway down the canyon…