Despite lore to the contrary and a bevy of chemical preservatives, the official shelf life of Hostess’ golden, cream-filled Twinkie is 45 days. But that hasn’t stopped people from pushing the envelope.

Two weeks ago, Colin Purrington took a bite out of an eight-year-old Twinkie he remembered stashing in his Pennsylvania basement. “When there’s no desserts in the house, you get desperate,” Purrington tells Nell Greenfieldboyce of NPR. Purrington purchased the Twinkies in 2012 as an edible memento, when Hostess declared bankruptcy and many feared the iconic American snack would disappear forever.

The Twinkie was old, sure, but it looked perfectly fine, and he was “just so bored, with the pandemic,” Purrington tells NPR. “It’s terrible, but it just is mind-numbing after a while.”

But the Twinkie’s enduring good-looks, it turned out, had deceived him: “It tasted like old sock,” he tells NPR. “Not that I’ve ever eaten old sock.”

Things took a more scientifically interesting turn when Purrington took out the remaining three cakes inside the package. One looked similar to the one he’d sampled while another had a concerning brown circle the size of a quarter, but the third Twinkie had undergone some kind of transformation.

The miniature cake’s yellow, spongy exterior had been replaced by a dull brown mass of hardened vermicular coils. Curiously, the Twinkie had also vacuum sealed itself inside its plastic wrapping, with the film coating every nook and cranny like a second skin.

A bit horrified, Purrington posted his find to Twitter, wondering whether what he was looking at was “something a fungus or bacteria does” or if there was “some abiotic chain-reaction taking place.” If you’re detecting a scientific bent to this line of inquiry, it’s because Purrington is a former biology professor.

The photos also caught the attention of fungi researchers Matthew Kasson and Brian Lovett of West Virginia University, who have previously experimented with the decomposition of other sugar-filled snacks. To Kasson, the unappetizing Twinkie “look[ed] like a mummy finger,” he tells Susie Neilson of Business Insider.

Kasson and his colleagues arranged for Purrington to send the Twinkies to their lab, where they excised core samples from the snack foods using a bone-marrow biopsy tool, per Business Insider. The mycologists then placed the array of samples in lab dishes along with some nutrients that would promote the growth of whatever fungi had colonized the Twinkies.

One Twinkie contained a type of Cladosporium. “Cladosporium is one of the most common, airborne, indoor molds worldwide,” Kasson tells NPR, adding that they can’t confirm the species until they conduct a DNA analysis.

Surprisingly, the samples taken from the mummified Twinkie didn’t instantly sprout any horrifying fungi. According to Business Insider, this absence is likely because whatever fungi were eating the Twinkie had long since died inside its packaging, perhaps running out of oxygen or food.

Kasson tells Dan Avery of the Daily Mail that his lab intends to place the shriveled Twinkie under an electron microscope, to examine it at 100-times magnification. The experiments may not end in any major discoveries, but Kasson tells the Daily Mail he’s excited about the attention the story has gotten for science and the sometimes-misunderstood fungi of the world.

“Fungi are often portrayed as bad, like fungal infections or the frog-destroying fungus,’ Kasson tells the Daily Mail. “But fungi are always there in the background doing their job, breaking down complex substrates for other organisms to use. They’re in the beer we’re drinking, the bread we’re eating—blue cheese, even!”