When Samantha Cocuzza plays with her two kids in their Townsville backyard, most of the time she has to hold her youngest off the ground.
It's not the prickles, or even the heat — it's something far more sinister.
As soon as her kids put their feet back on the grass, they're covered in an acid-spitting invasive ant species called yellow crazy ants.
"It's now at the point where they play outside in the yard, head in for a bath, and sometimes there are ants in the bath that come off the kids," Ms Cocuzza said.
The ants are categorised as one of the worst invasive species in the world, capable of completely destroying ecosystems and making outdoor areas virtually unusable.
The ants don't bite, but instead throw acid, which can burn the eyes and skin of people, and can blind and kill insects and small animals.
While one or two of the ants are rarely a problem, the species tends to congregate in incredible numbers.
They hold the world record for population density, with scientists recording 2000 of them per square metre.
In Townsville, where Samantha and her family live, an outbreak has been growing for years, and it finally made its way to her backyard in November last year.
She now has to spray the verandah regularly and sweep the ants away every day.
"And they've just multiplied," she said.
A town fighting on its own
The ants are not just a nuisance.
According to the International Union for the Conservation of Nature, they are among the 100 worst invasive species in the world.
On Christmas Island, off the coast of Western Australia, the ants have completely transformed the forest and decimated its famous red crab population.
It's not known exactly where they came from, but it's thought either Africa or Asia.
They were first detected in Australia in 1980 at Arnhem Land, although they were likely here much earlier. In 2001, they were found in Cairns, a few hundred kilometres north of Townsville.
About $30 million of state and federal money has been thrown at righting the infestation in Cairns — with eradication possibly in sight.
But so far, virtually no state or federal funding has been spent fighting the outbreak in Townsville.
The job of repelling the tiny invaders is the responsibility of the Townsville City Council, and the two technical officers who work there.
Yet their job also involves dealing with every other invasive species in the area including plants, pigs and deer.
Councillor Maurie Soars said the city was at a crucial juncture.
"We're at the tipping [point] now," he said. "Our experts here [are] telling us that we've really got to address it now.
"And if we do [that] we can have some serious impact on the spread."
The council said it wouldn't be able to stop the infestation, or even know exactly the full extent of the infestation, without significant funding from the state and federal governments.
"We are hoping that upper levels of government will start looking at it more seriously and then bring it in because if we don't stop it here, where are you going to stop it?" Mr Soars said.
Environmental charity The Invasive Species Council has assessed the situation in Townsville and is proposing a $27.6 million plan, which it thinks should be able to eradicate the ants.
So far, the ants have been found at about seven locations in Townsville, covering an area of hundreds of hectares — but the council doesn't have the resources to determine exactly how big the spread is.
A spokesman for federal environment minister Sussan Ley said the Morrison government has spent millions helping to control the outbreak near Cairns, but beyond that, it was the job of the state government and the council.
A spokesman for the Queensland agriculture minister Mark Furner said councils have received money from the state government to help with the control efforts.
"The ants are a declared pest, so landholders have a general biosecurity obligation to manage such pests on their land," the spokesperson said.
Perfect storm invaders
At Alligator Creek in Townsville, where Samantha lives, the ants are just 5km from Bowling Green National Park, where unique species such as the Mount Elliot crayfish and the Mount Elliot nursery frog live — species only found in this part of the world.
In the right location, Ben Hoffman said the ants could completely transform an ecosystem.
On Christmas Island, as well as killing millions of its famous red crabs, they also ate all the insects that fed on young plants, turning its sparse understorey into a dense bush.
"The transformation [there] is just so dramatic, it's unbelievable," Dr Hoffman said.
"You might as well be looking at two different island ecosystems where the ants are present in high abundance and where they're not."
He said there were a few elements that make them such incredible invaders.
Firstly, while most ant species have separate colonies, each with one breeding ant called the queen, there's no limit to how many queens a yellow crazy ant nest can have — with all the queens making babies.
And while different colonies of many ant species compete and even fight, yellow crazy ant colonies cooperate and combine.
"They basically cooperate as one massive nest that can cover tens to even hundreds of hectares," he said.
"It's almost the perfect storm of a species."
Once the infestation gets too big, eradicating it will be nearly impossible, according to Dr Hoffman.
From that point, the Townsville infestation will almost certainly lead to outbreaks elsewhere around the country.
That's no idle concern. Already, outbreaks in Darwin and on Hamilton Island are thought to have been seeded by the Townsville infestation.
Property prices impacted
Just up the road from Samantha live Vaughan and Yvonne Benn, both in their 80s.
They are too frail to fight the ants at the perimeter of their home, like Samantha does, and as a result, their home is crawling with yellow crazy ants.
"They crawl all over you," he says. "You wouldn't think a little thing like that would have much acid to squirt out but apparently they do."
As they watch TV, the couple say they have to brush the ants off their arms.
And they worry about what the ants will do to the environment around their home.
"They kill off the frogs and I believe they kill snakes," Vaughan said.
In their old age, the pair are planning to move towards town where they can access more care. But they're worried they won't be able to sell their home.
"You'd hate a prospective buyer to come out and say 'oh what's all these ants,' you know? You don't want that."
So Vaughan and Yvonne need the ants gone.
The ant fight
With the Townsville City Council now stretched beyond capacity fighting the infestation, local residents — with the help of environmental charity the Invasive Species Council — are taking matters into their own hands.
On a Sunday afternoon, more than 20 local residents meet at the property of Ian and Frances Cotrell, who are also facing a severe infestation.
The meeting is led by Bev Job from the Invasive Species Council, who is handing out supplies of bait, paid for by the charity, and explaining to the residents how to use it.
But she is frank about the likelihood of getting much done without assistance from the state and federal governments.
"Unfortunately, it's been left too long," she said.
"Now it's been left up to the point where there are not enough resources in the Townsville City Council."
The residents are taken around Ian and Frances' backyard, and shown what the ants look like, and where to find them — which is not difficult, as they're everywhere.
And according to Ben Hoffmann from the CSIRO, the infestation that's visible from the surface is just the "tip of the iceberg".
"The yellow crazy ant can be absolutely anywhere there's a cavity.
"So it's a hole in the ground, or it could be at the top of a coconut palm, for example. There's a lot of ants that you don't see.
"We only discover this when the ant gets into new locations [and] my personal preference is that we don't get to that stage."
