A tree branch fell on a roller coaster at the Six Flags Magic Mountain amusement park Monday evening. Four people were injured but it's amazing more were not hurt or even killed. The video is scary, but the good news is no one was seriously hurt.

The Ninja ride is described on the Six Flags website as the 'stealth assassin.' It's also called a 'black belt of roller coasters (that) whips you into submission.' The site claims the coaster whips 'around at 55 miles per hour.' But on Monday night, it was a tree branch that fell across the track, striking one of the cars, that brought the roller coaster to a stop.

Officials say it was not an easy rescue, as the roller coaster winds through treetops. Riders were left dangling beneath the track for hours as rescue workers secured the car and then were able to remove them.