The family’s nightmare started shortly before 9 p.m. Saturday night near the fastest roller coaster at Six Flags Great America in Gurnee, an Illinois town about an hour north of Chicago.

A couple and their 12-year-old son were in line near the “Raging Bull” ride during the amusement park’s annual Halloween-themed “Fright Fest” when a group of teenagers cut in front of them, authorities told the Chicago Sun Times.

The boy’s 50-year-old mother reportedly asked the teens to tone down their language.

That’s when the first punch was thrown, Gurnee police say.

One of the teenagers allegedly “sucker-punched” the 12-year-old. When his parents tried to help, at least nine teenagers surrounded them —  kicking, punching and stomping until the parents and their child fell to the ground, Gurnee Deputy Police Chief Brian Smith told the Chicago Sun Times.

The Washington Post could not immediately reach Smith for comment.

Police described arriving at a chaotic scene.

“It’s a Whack-a-Mole [attraction] now,” one officer yelled as police tried to contain the fight.

“For everybody rolling up to them, they’re pretty mouthy,” another said, as they followed the teens to the parking lot.

Numerous witnesses reportedly called 911. Eventually, Six Flags security stopped the attack and the family was taken to the hospital with “significant” injuries, though none life-threatening, Smith said.

Smith said the annual attraction usually draws “an increased number of knuckleheads who come to stir things up,” but nothing like the attack on Saturday.

“This is rare. This is on a different spectrum,” Smith told the Chicago Sun Times. “This family is lucky they got out with just the injuries that they did.”

Smith told the Chicago Tribune that police made a “tactical decision” to allow the group to leave the park, rather than confronting them inside of it, which police believed would lead to more injuries.

But security was trailing the group, and several police were stationed on the road outside the park, where they arrested the suspects without incident, according to the Tribune.

Gregory Battle, 18, was charged with aggravated battery causing great bodily harm, mob action and aggravated battery in a public place, according to police. He was released after posting bond earlier this week, according to the Chicago Tribune. His next court date is Oct. 25.

Eight other juvenile suspects, ages 15-17, were named in juvenile petitions for mob action and taken to the nearby Depke Juvenile Complex Center in Vernon Hills, the Tribune reported. Smith said it is possible that some attackers got away.

The park advertises Fright Fest as a “spooky time of year” when “zombies and ghouls take over the park.” It began Sept. 16 and runs through Halloween.

“The stuff of nightmares lurk around every corner as the dark of night washes over the park,” the park’s website says. “The ghouls are set free for their daily hunting rituals. BEWARE! There is no place to hide!”

Read more: