All are drawn to public meeting places by what appears to be an underage boy or girl.
They're in for a surprise, though: It's actually a Hudson County native who calls himself XK.
"I'm not here to hurt you," XK tells those who show up, recording every second of the encounter on his GoPro. "I just want to have a civilized conversation with you."
Ten minutes or so in, XK asks the target if he likes ice pops.
"I like firecracker ice pops. That's my favorite," he tells them.
That's the signal for legions of followers watching the live stream to immediately call police. Moments later, uniformed officers arrive and make an arrest.
One of XK's recent catches was a teacher's aide, another a paramedic. One had a 15-year-old son and 8-year-old daughter. Then there was a dean from St. Benedict’s Preparatory School in Newark.
Dangerous? Yes. Legally squishy? For sure.
Amateur predator hunting has become a growing trend, however.
It was initially fueled by "To Catch a Predator" -- a TV series that was canceled in 2008 after a target killed himself -- and has since taken on a life of its own. In just a single year, the online tracker Preds Exposed reported finding nearly a thousand stings by self-appointed predator catchers across the country.
Like his amateur colleagues, "Hunter XK" has no law enforcement or investigative experience.
Rather, the 30-something vigilante from Jersey City said he's developed a "skill set" from watching YouTube videos and paying close attention to the tactics that others use.
"I've picked up some cues from them," XK told Daily Voice following the arrest of one of his targets -- a teacher's aide -- during a meet-up in North Arlington.
It all began after he tagged along with another vigilante, XK said. He arranged a sting of his own last December and "realized it was something I wanted to do."
XK began in Hudson and Essex counties and only recently expanded to Bergen, which he says has been friendly to his cause. He funds the operation through clicks and donations.
XK creates bogus profiles on Grindr, Tinder, and other apps where adults might try to lure vulnerable, unsupervised children. He's posed as anything from a 13- to 15-year-old boy or girl. Adult friends who look underage give him photos that XK posts with the profiles.
Then he waits.
"At least 85-90% reject me when I tell them the age," he said, "but the remainder want to meet up."
Several even send you-know-what-kind-of pics.
Once they ask to meet, XK gives them an address. Then he goes live with a lighted GoPro, a Samsung Android "decoy" track phone and his main phone.
XK prefers confronting his targets in building vestibules with active video cameras for third-party recorded protection.
"This way they can't say that I hurt them," he said.
Although he's used adult friends as decoys, XK ordinarily rides solo.
Overall, XK says he's met up with nearly 50 men looking for sex with underage boys or girls. Ten or so have been arrested on the spot, he said.
XK gives responding officers all of the evidence, including SD cards. He'll spend hours at various police headquarters, however long it takes, providing statements and information.
He then posts videos of the encounters on the New Jersey Predator Intervention YouTube channel (nearly 5,000 subscribers), complete with a lengthy disclaimer at the beginning of each.
XK has family members and friends who were molested or raped as children, but there's no deep-seated motivation. If he makes a potential child abuser think twice, he said, he's done his job.
Authorities for years have had specially trained investigators pose online as underage targets to reel in potential predators.
Although they publicly condemn undercover civilian sleuthing, they continue pursuing the cases that are brought to them. This past summer, police in Atlantic City arrested 17 men in a two-week stretch of "concerned citizen" stings.
So far, a local Hudson County police chief has been the only law enforcer to give XK a hard time. The chief, who seized his equipment and kept it for nearly a month, said he should simply bring the evidence to police and not try to play cop himself.
There certainly are risks. You could damage the reputation of a perfectly innocent person -- not to mention being held liable for it. And, technically, receiving and storing an image of child sex abuse from a target is a felony itself.
An amateur could also end up blowing a case that sworn law enforcers have already been working on. Or, worse, they could embolden predators who don't take the bait to pursue what turn out to be real children.
You could also get shot, as one discovered.
"I have thought of that," XK said. "But I have my own protection -- Mace. And I am really good with my hands."
He also repeatedly tells the targets to keep their hands out of their pockets -- and even has some turn their pockets inside out.
Passersby usually keep going during an encounter, many seemingly without noticing. Now and again, someone stops. A driver recently pulled out his cellphone and began recording an encounter himself.
XK's profile is steadily increasing.
"Two weeks ago a guy from Bergen County thought he was talking to a 15-year-old girl," he said. "Then something made him stop. He said, 'Nah, you're that guy who goes around catching predators.'
"He never showed up. He blocked me instead."
There have also been artists, architects and designers, among other gainfully employed men whom he's targeted.
"A lot of these guys have real jobs. One had two jobs," he said. "Still they take the risk. It makes me wonder how many boys they've looked at or been with."
Didier Jean-Baptiste, 54, of Jersey City lost his job as a dean of seniors at St. Benedict's Prep after he was arrested during a meeting with XK in Harrison last month. Authorities charged Jean-Baptiste with attempted luring and child endangerment.
Donald Knight-Powell, a teacher's aide from Bloomfield who was caught earlier this month in North Arlington, knew who XK was. Knight-Powell drove off, then returned, then tried to drive off a second time when police arrived. He was quickly arrested on similar charges.
Another target who showed up on Thanksgiving Eve is seen on video standing in the same North Arlington vestibule where XK met Knight-Powell.
"This guy came here to meet who he thought was a 14-year-old boy. I got the chat logs and everything," XK says. "He told me the things he wanted to do with him. He was told the age. He wanted to come over to the boy's house.
"At some point he asked him if he was top or bottom. That's not something you should be asking a 14-year-old boy or any underage (child)."
The man -- later identified as Efrain Roman, 43, of the Bronx -- is wearing a hoodie, shorts and sandals with white socks despite temperatures in the mid-40s. His cellphone is out as he stands at a locked door, apparently waiting to be buzzed in.
"I'm here to have a conversation with you," XK tells him. "This camera is rolling for your safety and mine. I'm not here to hurt you. I want no money from you."
Roman admits that the boy who invited him over claimed to be 14 years old but that "sometimes they say that" even though they're really 18 or 19.
"Once someone tells you they're underage, you're supposed to block them," XK tells him. "It's not what you believe. It's what they tell you."
"My bad. My bad, bro," Roman replies. "I f*cked up....I'll never use the app again. I swear."
He starts to cry, repeatedly says "I'm sorry," then starts fiddling with his phone.
"It doesn't matter if you block me. I got everything screenshot," XK says. "I'm not here to judge you. I'm here for some understanding."
Roman says this is his first time.
"You know how many people say that?" XK responds. "We hadn't even talked 45 minutes and you were all ready to meet up with him."
XK pauses, then asks a fateful question.
"You like ice pops?"
Click here to follow Daily Voice West Chester and receive free news updates.