Uncooperative horses wreaked havoc and killed dreams in the weirdest event at the Olympics

• Uncooperative horses caused chaos and killed dreams during the Olympic modern pentathlon.
• Horses bucked off their riders, refused to jump fences, and generally caused mischief.
• One athlete slipped from first to 31st when her horse refused to jump. Another was thrown twice.

There's an old saying in show business: Never work with children or animals.

That rang true on Friday as badly behaved horses wreaked havoc during the Olympic modern pentathlon.

The event, created for the Olympics, pits athletes against one another in five disciplines: fencing, swimming, riding, running, and shooting. It's designed to reflect the tasks of soldiers in the 19th century.

It's as wacky as it sounds. Invented by Pierre de Coubertin, the father of the modern games, the event has appeared at every Olympics since 1912.

At Tokyo, four of the five portions went off without a hitch. But the riding portion was plagued by chaos caused largely by the horses.

To ensure fairness, competitors aren't allowed to bring their own horses - they must ride a horse randomly assigned to them 20 minutes before they ride.

The athletes are then awarded points based on how quickly and cleanly they complete a show-jumping course.

It's simple in theory. But horses sometimes simply don't want to do what you want them to do.

Unfortunately for several competitors in Friday's modern pentathlon, their horses decided they did not want to play ball.

The most notable and brutal incident involved Germany's Annika Schleu and her new equine companion, Saint Boy.

Schleu led the pentathlon going into the show-jumping competition but plummeted as Saint Boy refused to jump over many fences, leaving her unable to finish the course.

So belligerent was the horse that Schleu was reduced to tears while on his back.

Schleu didn't score in riding and eventually finished 31st. But it may be some comfort that Saint Boy didn't seem to have anything against her personally.

The horse also refused to jump for Russia's Gulnaz Gubaydullina, who finished 32nd, also not scoring in riding.

Saint Boy wasn't the only tearaway horse - six athletes didn't score thanks to their badly behaved mounts.

Italy's Elena Micheli, who was in a strong position after the fencing and swimming portions, was particularly hard done by her horse, Cristbal 21.

If Saint Boy was the horsey equivalent of a grumpy teenager, Cristbal 21 was even worse, bucking Micheli off twice and even running straight through one fence.

Brazil's Ieda Guimaraes also registered a zero when her horse, Caleansiena YH, went rogue and threw her off.

Naughty horses cost a medal shot

While Saint Boy, Cristbal 21, and Caleansiena YH were extreme examples, other horses were also uncooperative.

Constantin, ridden by Uzbekistan's Alise Fakhrutdinova and Ireland's Natalya Coyle, notably refused to jump several fences, which could have cost Coyle a chance at a medal.

Fourth before the riding portion, Coyle scored 234 points in the riding, 60 fewer than Kate French of Great Britain, the eventual gold medalist. Coyle ended the pentathlon 24th, 117 points off the lead.

Coyle's disappointment caused outrage on Irish TV, with the former Olympic pentathlete Hugh Forde telling RTÉ, "To be quite frank, it's not good enough.

"Those horses have been tested around those tracks, but that behavior from that animal, you would expect a higher standard at this level," Forde said. "It's too cruel."

Forde added of Schleu, "Everything she worked for is out the door because of that horse."

French won the pentathlon with 1,385 points, breaking the Olympic record.