One moment the helium balloon was up in the air, and the next, it plunged 20m (about seven storeys) to the ground after springing a leak.
Four of the people in the balloon were lucky to escape without injuries. Four others suffered minor injuries or shock. And a hapless visitor on the ground was hit by the falling balloon and suffered head injuries.
The accident happened in Hong Kong's Ocean Park on Thursday, Hong Kong Standard reported. It is the worst accident since it opened 35 years ago.
Seven park visitors and the operator were in the SkyStar ride when the balloon failed.
Said one injured visitor: "It happened so quickly. I didn't even know what was happening. One moment we were up in the air and the next we hit the ground."
Two women with arm and leg injuries were taken to a hospital, but were discharged after treatment, the report said.
Government and Ocean Park engineers have launched an investigation. The park officials must submit a report to the government within a week.
The SkyStar has been in operation since 2007. The balloon is 22m in diameter and 34m tall. It can carry up to 30 people and rise 100m to provide a majestic view of southern Hong Kong.
Ocean Park engineering executive director George Tso Chi Keung told The Standard that the balloon operator realised there was a leak in the balloon from readings on the helium gauge in the steering compartment.
Said Mr Tso: "Normally, it would fall gradually from a height of 60m. However, when it was about 20m from the ground, it fell quickly - faster than the normal 0.6m per second."
What caused the balloon to descend rapidly was a rupture in the gas-filled bag. Park officials did not give any details of the tear, but some witnesses were quoted as saying that it was more than 3m wide.