More than two dozen men thought they were meeting with underage teenagers for sex.
One brought condoms and alcoholic beverages to the rendezvous. Another one brought along his toddler.
Instead, authorities say, the 25 men were met by uniformed officers.
The men were arrested as part of an investigation targeting predators who solicit sex from minors online, according to the Harris County Sheriff's Office in Texas.
For three days last week, investigators with the sheriff's office's High Tech Crime Unit posed as underage kids, between ages 11 and 15, as they talked to the suspects online and agreed to meet with them at certain locations, according to media reports.
The men, whose ages range from 20 and 48, were arrested last week, according to ABC affiliate KTRK-TV. They have been charged with online solicitation of a minor, a second-degree felony.
Harris County Sheriff Ron Hickman said the decision to bring along a toddler to the meetup is "one of the dumbest things I have ever heard," ABC affiliate KTRK-TV reported.Seven of the suspects showed up armed. One, a security guard who pretended to be an officer from a nearby county, brought alcohol and 25 condoms with him, according to KHOU-TV. Another one showed up with his 2-year-old son, the TV station reported.
"But clearly these people do not care about anyone except themselves. I mean, the height of selfishness, I mean, he brought this 2-year-old child literally on his hip," Hickman told the TV station.
About a week ago, 22 men, including a pastor who volunteered in schools, were arrested after a five-day undercover police investigation in Pensacola, Fla. The men showed up at certain locations with drugs and sex toys, police said.
In May, 32 men and women, including two pastors, were arrested in an undercover human trafficking and prostitution sting by the Tennessee Bureau of Investigation.
Sting operations have migrated from chat rooms to apps and social media, where young people socialise and predators can establish contact, Polk County Sheriff Grady Judd told The Washington Post's Peter Holley earlier this year. In April, investigators from Judd's office arrested child predators from Disney and SeaWorld, as well as a Christian football coach.
"They used to have to hang out in parks and coach Little League or teach Sunday school in the past," Judd said in April. "Now they can download an app and look for kids that are in need of attention - boys and girls. When a 60-year-old man wants to have sex with a 10-year-old child, those are the most dangerous of the dangerous."
In the Harris County case, authorities say the men used smartphone apps and online chat rooms to start conversations with people they thought were children. One used the name "Bear Hug," while another used "somefun4unme."