Seaside Aquarium thought a common sunfish had washed up on the Oregon coast last week and posted photos of its 2,000-pound carcass on social media. But a New Zealand-based marine biologist who saw the photos suspected they had stumbled upon something far more rare — a hoodwinker sunfish.

The aquarium’s mistake was understandable. It’s one people and scientists made for more than a century, until it was identified as a different species. In fact, it’s why marine biologist Marianne Nyegaard had given it a name alluding to its ability to fool people. Last week, she came across the Seaside, Ore.-based aquarium’s photos and contacted employees there to let them know she believed they had found one of the tricksters.

“I saw this and went ‘Wow! This is a hoodwinker,’” she told The Washington Post.

The carcass of the fish, which the aquarium believes to be one of the largest specimens ever documented, is just over 7 feet in length and bizarre-looking – like a bloated skipping stone with dead eyes and a lipless mouth. Its creepy appearance notwithstanding, the corpse has drawn sizable crowds in person and online ever since came ashore a week ago, said Seaside Aquarium general manager Keith Chandler, adding that the number of spectators numbers in the thousands.

“It’s been a crowd pleaser,” he said, adding, “The social media went crazy on it.”

It’s the latest twist in Nyegaard’s career studying sunfish, one that’s spanned more than a decade and thousands of miles as she’s tried to identify the hoodwinker, which she named Mola tecta, with “tecta” meaning covered or hidden. In doing so, she’s had to differentiate it from the common sunfish Mola mola, which was identified in 1758.

In 2009, Japanese researchers released a genetic study that revealed evidence of an unknown sunfish species called Mola species C, according to Nyegaard’s 2017 research paper published in Zoological Journal of the Linnean Society. “But the fish kept eluding the scientific community because we didn’t know what it looked like,” Nyegaard said in a Murdoch University news release announcing the discovery she and her team had made.

“Finding these fish and storing specimens for studies is a logistical nightmare due to their elusive nature and enormous size, so sunfish research is difficult at the best of times,” Nyegaard wrote.

Its existence would take time and effort to confirm. Over three years, Nyegaard and her co-authors collected data from 27 specimens of what would become known as the hoodwinker sunfish, traveling thousands of miles or relying on other researchers to take samples of sunfish found stranded on remote beaches, according to the university’s statement.

“The new species managed to evade discovery for nearly three centuries by ‘hiding’ in a messy history of sunfish taxonomy,” Nyegaard said.

Hoodwinkers look superficially similar to other species of sunfish but are easily distinguishable upon examination, she said. For example, Mola mola have wrinkly skin, whereas hoodwinkers are completely smooth. One of the reasons it took so long to differentiate species of sunfish is that there’s not a lot of money flowing into researching them.

“We only gain knowledge when someone’s actually looking at it,” she said.

According to Nyegaard’s team, the hoodwinker was the first new species of sunfish discovered in more than 125 years.

At first, Nyegaard believed that hoodwinkers lived exclusively in the southern hemisphere, she told fellow sunfish researchers in 2021. She had found evidence of them in temperate waters off the coasts of Chile, South Africa, Australia and New Zealand, and thought a large band of warmer water blocked them from going north.

But in 2019, one washed ashore in California, and since then, they’ve been found up the West Coast into the Pacific Northwest and as far north as Alaska, she said during her 2021 presentation.

Upon hearing the news of a new hoodwinker specimen, Nyegaard, who happened to be traveling in Seattle last week, made the 4½-hour drive to Gearhart to investigate, Chandler from the aquarium said Monday. Once there, she took samples, including the fish’s ovaries, while spending two hours answering any and all questions spectators had about the species she had recently discovered, Chandler said.

“She was just as happy as any person I have ever seen,” he said.

The carcass withstood the elements and scavengers because of its tough skin, Chandler said. But after Nyegaard cut into it, he suspects bald eagles, sea gulls and the like will start to pick away at it. Still, he said he’s glad it’s drawn crowds out into nature and, for a lucky few, exposed them to an interactive learning session with a researcher actively gutting a specimen.

“If it gets people off their phones out of their basements onto the beach,” Chandler said, “it’s a great thing.”