It's the bizarre frog of legend that swallows their own fertilised eggs, incubating them in its stomach before spitting out baby frogs once they have grown.
But a last-ditch effort by scientists to find the Eungella gastric-brooding frog in remote rainforests of north Queensland have proved unsuccessful, all but confirming the critically endangered species is extinct.
Dr Conrad Hoskin, a tropical biologist from James Cook University, was one of several scientists who travelled by helicopter into the western side of the Eungella range, spending three nights camping and surveying the creeks for signs of frogs.
He had hoped that the isolated location, along with the warmer conditions might prove to be a refuge for endangered frogs to survive and live with the devastating chytrid fungus.
"We often find a species we thought was extinct in these areas where the disease is present, but doesn't impact the frog population as dramatically," Dr Hoskin said.
As a final confirmation, water samples have been taken from the sites to be checked for any residual DNA from the frogs upstream.
From critical to extinct
The Eungella, or northern gastric-brooding frog, was the larger relative of the southern species, last seen in the wild in the late 1970s or early 1980s.
While the southern species has been believed to be extinct since the 1980s, some scientists had held onto hope the northern species was still living and hiding in the cold streams of largely inaccessible country.
"It [the northern gastric-brooding frog] sits at critically endangered, and that's on the cusp of going extinct now," Dr Hoskin said.
But while Dr Hoskin believes this was the final search he will undertake for the elusive amphibian, he was excited to also find populations of other critically endangered frogs on his trip.
The Eungella day frog, Eungella tinker frog and the tusked frog were all identified by Dr Hoskin on the trip, two of which are endemic to the region and found nowhere else in the world.
"It's obviously really sad [to presume to Eungella gastric-brooding frog as extinct] but it means you probably then start investing your resources in the next most threatened things," he said.
Life finds a way
Now, scientists from across the world have banded together in an extraordinary effort to undo the extinction of the exceptionally unusual frog.
Mike Archer, professor of Biological Science at the University of New South Wales, put together a team of scientists from as far away as Mongolia to work on cloning a southern gastric-brooding frog from a frozen sample.
"It was an individual that was in a breeding colony in the University of Adelaide about 40 years ago," Professor Archer said.
In 2013, the team had success in a somatic cell nuclear transfer.
"This is where you take the nucleus from the cell of your extinct species and inject that into an enucleated cell of a related living species, in an egg," Mr Archer said.
After hundreds of trials, they successfully transferred a cell, and started to divide it into a ball of cells.
While they could confirm it was the DNA of the extinct frog that was building and replicating cells, the process stopped as quickly as it started.
To the scientists' disappointment, the cells did not go on to develop a more complex embryo, which would have gone on to become a tadpole.
Trials doing the elaborate cell transfer on other, living frogs also proved unsuccessful, meaning the technique rather than the frog's DNA was at fault.
'Beyond the edge of known science'
The team is now experimenting with these procedures and looking for alternative approaches.
But there is no way to know when they could make a breakthrough, and Professor Archer knows other challenges lie ahead.
"When you're at beyond the age of the known science, there's no signpost to tell you how much further you have to go to succeed," Mr Archer said.
"In life the gastric-brooding frogs, the females swallow the fertilised eggs, but we don't have any adult females anymore to do that."
While the experiments are being undertaken on the southern species of gastric-brooding frog, the team do have a frozen northern frog sample.
The technology isn't reserved solely for frogs, either, with Professor Archer already worked on a project that has sequenced the whole genome for the Tasmanian Tiger [Thylacine].
"If we are responsible for having seen species declined to the point of extinction, I really think we have a moral responsibility to step in," Mr Archer said.
"If the technology is there, or even if we need to build the technology."
"It's about trying to demonstrate that we can fix what we've broken."
