A Colorado Springs, Colo., teenager was in critical condition Wednesday after tumbling from the back of a moving car while car surfing.

Terence Henderson, 17, was riding on the back of the car as it drove 30 mph down Walton Creek Drive Tuesday and the 17-year-old driver began fishtailing in a light-hearted effort to shake Henderson off the trunk, investigators said.

Henderson fell onto the road and rolled several times, knocking him unconscious. He was rushed to Memorial Hospital with head injuries.

"It is pretty reckless," Colorado State Patrol Trooper Pat Serrant told the Colorado Springs Gazette. "He was just trying to get him off the vehicle, not realizing he was responsible for his actions. They were just having a good time."

The driver's name was not released because investigators have not decided if charges will be filed.

Two teenagers died in separate car-surfing accidents in Colorado last year.