Disturbing dashcam footage shows a boy lying in the middle of a busy Perth road, before terrifying a motorist in an apparent prank.

The clip, recorded early morning of December 16 and shared to a local Facebook group this week, warned of a youth “pranking people” by appearing injured.

The boy was seen face-down, about 5am on the left lane of Spencer Road in Thornlie, forcing the approaching motorist to pull up to avoid running him over.

View photos Dashcam footage shows a Perth boy lying in the middle of a busy road. Source: Thornlie WA Crime/Facebook More

When the driver slowed to a stop, the teen reportedly got to his feet and approached the car with his arms outstretched.

Watching the odd behavior unfold, the driver locked the doors then reversed slowly away from the boy.

View photos When the approaching motorist pulls up to avoid running the youth over, the boy rises to his feet. Source: Thornlie WA Crime/Facebook More

The boy pretends to launch towards the windscreen, causing the occupants to swear, before the driver manages to avoid hitting him as the vehicle speeds away.

"Lock your car doors and do NOT stop, go around," the motorist who recored the dashcam footage wrote with the video post on the Thornlie WA Crime Facebook page, on Thursday.

View photos The boy creepily approached the car with his arms outstretched in an attempt to spook the occupants. Thornlie WA Crime/Facebook More

Others who viewed he clip on the social media page reported to have encountered the boy doing the same thing to other motorists in the area, according to WA Today.

The driver added that they reported the incident to the police.

Anyone with information is encouraged to call Crime Stoppers 1800 333 000 or use the Crime Stoppers online reporting page.