Here's a video that will make you wince - a group of mountain bikers in Spain who were attacked by a swarm of bees.
Just looking at the footage is painful, and we reckon the fact that two of the riders dumped their bikes altogether shows how intense it was.
The incident happened in March during the Tropical Bike Motril competition in Spain.
José Miguel Rodríguez, the vice-presidente of the organising group, was stung 80 times and had to be treated at a hospital in Granada, as did four other competitors.
"I've never suffered so much," he said.
"When I got home my wife was frightened. I had to take anti-histamine medicine."
He added: "I feel really bad at night."
At 37 seconds into the video, you can see a beekeeper on the right-hand side of the screen.
Bees can feel vulnerable when their hives are disturbed, making them more likely to attack as a means of defence, while some species in Spain and elsewhere can be attracted by human sweat.