Whoops of joy and laughter erupt when a randomly chosen victim is whacked with a baseball bat from a passing car. All of it, and more, is captured on one of America's scariest home videos.

"Bashing" is what the four chortling teenagers inside the car call their sport. One of them described it as "human head baseball."Several times they videotaped themselves nailing their victims with bats or paint-ball guns, right up until a police car caught them and officers confiscated the videotape as evidence.

"Uh oh," one of them said just before the tape ends.

Even after 24 years of experience with crime in this city, Deputy District Attorney Robert L. Cohen called the taped evidence "blood-curdling."

"The more you watch, the angrier you get," Cohen said Monday. "The potential for grave injury was great in this mess."

Nobody was seriously injured in the random attacks in which the victims were hit with bats all over their bodies, including the face.

The 20-minute video shows the four teenagers cruising the bleak, nighttime streets of the suburban San Fernando Valley, alternately finding people or vehicles to bash with a bat or shoot with the high-pressure paint gun.

"That's what this sport is about . . . making people cry," one of the youths explains. Adds another, "I hit them hard."

They laugh, hoot, swear and promise more violence and vandalism as they race past a Taco Bell, a strip mall and down a series of dark, meandering streets in their little economy car.

A man waiting for a bus is hit with the paint gun, and so are several pedestrians and a homeless woman on the pavement next to her shopping cart of aluminum cans.

The car pulls up. One of the four asks for spare change, then a rapid-fire fusillade of orange paint pellets hits the shopping cart's owner, making her writhe.

"Life's a b----," one of the youths shouts as they speed off in search of another target.

The three 18-year-olds were being held in lieu of $100,000 bail. They could face up to 17 years in prison if convicted on charges of assault and felony vandalism.