A piano wire is stretched across a road at neck height, causing a motorcyclist to become decapitated as a result of running into it at high speed.
[1] There is also an urban legend of a 'headless biker gang', in which a group of headless riders explode on the mountain roads of Mount Hiko in Fukuoka Prefecture.
The film contained a scene in which a rider's head is chopped off by a wire stretched across a road, and this is said to have spread in connection with rumors of motorcycle accidents in various parts of the country.
The urban legend is said to have originated from an actual accident in which a person annoyed by a biker gang used a rope stretched across a road as an obstruction, causing the rider(s) to crash.
There are also reportedly some fun-loving riders who deliberately wear black, full-face helmets (which have been treated to reduce light reflections) at night in order to achieve this effect.