Around 1,000 people were dancing to music in a water park in Taipei, and people sprayed them with coloured powder.
The powder then caught on fire and burned at least 516 people. Nobody died, but 180 people had to go to intensive care. Some even passed out from the pain. Others had burned clothing stuck to their skin, or breathed in the powder which then caused them respiratory problems.
People are investigating the incident, and the use of this powder is illegal until the investigation is completed.