Things got super scary for guests of a Halloween event at California's Great America Saturday, but the fright didn't come from ghosts or goblins — instead, a large group of violent, larcenous teens was apparently to blame.

According to Santa Clara Police Department spokesperson Sergeant Dan Moreno, who spoke with NBC Bay Area, reports started rolling in at around 11:30 Saturday night, with callers saying that roving groups of young folks were getting into fights and stealing cell phones.

This was all during the amusement park's Halloween Haunt event, which on its website promises that "fear is waiting for you."

Fear and, it appears, "groups of roving thieves," the Chron reports, saying that "upwards of 100 people, mostly teens, were harassing guests" at the park.

Several park patrons reported being confronted by bands of youths in the park’s Halloween exhibits who took their wallets and phones. One visitor reported that a robber was armed with a Taser. Some of the victims fought back against their attackers, while others ran for the exits.

According to CBS 5, there was "no apparent reason" for the unrest.

"As one fight started between teens, other teens would swarm around to shoot video, which seemed to encourage more fights," they report.

NBC Area reports that "Footage shot from the scene captured screaming, people being pushed and a taser being used," the latter during an attempted cell phone theft.

In another case, witness Noe Bracamontes tells CBS 5 that she saw two girls hitting each other, then heard a "zapping" sound.

“We heard it and I was like, ‘Is that what I think it is?’ She just started like, Tasing the girl. Almost like stabbing her in a way,” Bracamontes told CBS 5. “It was chaotic. It was hectic.”

But the action seemed motivated less by an effort to profit and more from sheer teen angst, Bracamontes said. “Like, ‘Oh, he looked at me weird.’ Or ‘She’s looking at me weird'...Somebody bumps into somebody. There’s a lot of people there. Some might take it as disrespectful.”

In a written statement, Great America said that "There were incidents on October 28 at California's Great America that required assistance from on property Santa Clara police officers and were quickly addressed. The safety of our guests is our top priority."

According to CBS 5, however, a park spokesperson "insisted the park did not evacuate or close early."

But according to an employee that spoke to CBS 5 off camera, "once Santa Clara police officers arrived, they started ushering customers and some employees out of the park just after midnight, an hour before the parks scheduled 1 a.m. closing time."

Police tell ABC 7 that only two arrests were made, "one for theft by a juvenile and one for public intoxication." The rest of the suspects had scattered by the time they arrived, Santa Clara Police say, but asserted that they "plan to review security video in hopes of identifying and arresting more people."