The “Ice Poseidon Homeless Shelter” promised beds, free meals and security for people living on the streets in a Los Angeles region that has long failed to provide enough shelter space.

There was only one problem: it didn’t exist.

The address that was listed online for the supposed shelter in the San Fernando Valley was, in reality, the site of a private mansion. And the “Ice Poseidon” facility, displayed on Google Maps with photos of beds and a communal dining area, was apparently the creation of a group of online trolls.

Paul Denino, a YouTube personality known as Ice Poseidon, told the Los Angeles Daily News this week that pranksters had repeatedly listed his mansion as a homeless shelter on Google and had written dozens of fake reviews. As a result, homeless people seeking shelter and resources showed up at the mansion in Tarzana, a wealthy neighborhood that is home to country clubs and some of the most expensive homes in the area.

“I don’t think they realize how much of a horrible effect this has had on people who need the most help,” Paul Read, a local advocate for the homeless, told the Guardian. “All of these people said, ‘Finally, we get a shelter.’ They are desperate … and it just turns out to be an ultimate disaster.”

The fake homeless shelter is the latest example of a cruel online joke with devastating real-world effects. It’s what happens when a niche community of trolls manipulate a major online platform to spread false information, in the process punishing one of society’s most vulnerable populations.

“It’s already depressing enough out here,” said Rita Dunn, who is currently living in a tent by train tracks not far from the location of the fake shelter. “It is sad that people would waste their time in such a malicious way.”

Denino, who did not respond to the Guardian’s inquiry on Tuesday, gained popularity by livestreaming his daily life on YouTube, and a New Yorker profile of him last year reported that he was making tens of thousands of dollars a month in sponsorships and donations.

Fans have regularly tried to prank him while he has been live on the platform, calling restaurants where he was dining and saying he was a pedophile or had a bomb in his bag, the magazine reported. Other times, he was subject to “swatting”, a particularly dangerous internet prank where people call 911 with false reports of hostage situations, leading police to send a Swat team to people’s homes.

The origin of the homeless shelter joke was unclear. Denino told the Daily News that the Google listing was drawing dozens of homeless people to his house and that he had tried unsuccessfully to get the false location taken down. Denino told the paper he had since moved to Austin, Texas.

As of Tuesday, “Ice Poseidon Homeless Shelter” was still a suggested search in Google Maps, though clicking on it led to an error message saying: “There was a problem with that suggestion.” (Google Maps now also suggests an “Ice Poseidon” shelter in Austin, with a link that was similarly showing an error on Tuesday).

A Google spokesman, Paul Pennington, said the Ice Poseidon listing had been “corrected”, and he said in an email that spam and fraud was a continuing challenge: “We’re in a constant race with these scammers who, unfortunately, use all sorts of tricks to try to game our system. As we shut them down, they change their techniques – and the cycle continues.”

Of businesses people see on Google Maps, less than 1% were fraudulent, he added.

It’s unknown how many people may have been duped by this Google listing, but the impact for an individual could be severe, advocates said.

Dunn, a 39-year-old who has been living on the streets for almost four years after losing her home, said she had heard about a new Tarzana shelter, but ultimately decided not to check it out since she had previously had bad experiences with shelters.

“It got a lot of people’s hopes up,” she added, noting that people experienced “heartache” when they learned the truth.

Paul Read, the homeless advocate, said he first heard about the shelter about five months ago and that people seeking help had continued to ask him about it in the months since. With so few beds available in the region, some people were compelled to visit the shelter in person, he added.

“The amount of disappointment when people think they are going to be inside and then they get nothing … you can literally see people sink,” he said.

The LA region has a dramatic and worsening housing crisis, with the latest count estimating nearly 59,000 people across the county are homeless. More than 44,000 of those people, or about 75% of the homeless population, are unsheltered.

With resources concentrated in LA’s Skid Row and other densely populated areas, there are especially few options in the San Fernando Valley, west of downtown LA.

The Rev Andy Bales, CEO of Union Rescue Mission, an LA homeless organization, said he had heard about the fake shelter from news reports and added it was upsetting to think of people “rushing with their hopes up, and it ends up being a mirage in the desert”.

“Their first inkling might have been: ‘This is too good to be true.’ But people are so desperate, especially right now with the heat,” Bales added.

Read said he talked to some people who showed up at the fake shelter and were eventually confronted by law enforcement.