A supposedly thrilling ride down a ski slope inside a giant inflatable ball ended in tragedy for two Russian men inside.
One died and the other was badly injured when the transparent plastic ball - called a zorb - veered off course and sailed over a cliff in the Caucasus Mountains of southern Russia.
The men's terrifying ride - captured on video - prompted the head of the national emergency rescue services to demand on that Russia address its lax enforcement of safety rules for winter sports, citing a series of accidents over the January holidays.
The sport of zorbing originated in the 1990s in New Zealand and is now done around the world.
The man who died, 27-year-old Denis Burakov, was with friends at the Dombai ski resort, where they frequently went snowboarding, when he decided to take a ride in a zorb being operated next to a beginners' slope. His friend Vladimir Shcherbakov joined him.
An eight-minute video taken on Mr Burakov's phone by one of his friends shows the two men being fitted into harnesses inside the zorb, which consists of two polyurethane balls with a layer of air between them. The zorb is then released to roll down the hill, the two men spinning inside.
But the zorb bounces off of the intended path, and a man waiting for it at the bottom of the hill tries in vain to catch the ball before it pops over a rocky ledge and disappears down a gorge below Mount Mussa-Achitara.
The Emergencies Ministry said both men were ejected from the zorb as it tumbled and they landed on the snow. They were rescued by two skiers. Mr Burakov suffered serious spinal injuries and died on the way to the hospital. Mr Shcherbakov suffered a concussion and other injuries.
Sergei Loginov, deputy director of Z-orb.ru, the largest supplier of zorbs in Russia, said the run was conducted in violation of all safety rules. Zorbing requires a groomed gentle slope with fences on both sides of the track and a secure spot at the bottom where the ball can be safely brought to rest, he said.
"It's not even irresponsibility. It's an experiment on life. It's all or nothing. They either survive or they don't."