It sounds like a mad science experiment, or perhaps some bizarro superhero (or supervillain) origin backstory. Back in 1971, the largest machine in the world was a 200-billion-electron-volt proton synchrotron particle accelerator, today known as Fermilab, and it was broken. So researchers came up with an offbeat plan to fix it, by tying a string to a ferret and using the animal as an atomic age pipe cleaner, as explained by on the Fermilab History and Archive Project.

The plan was for the ferret, lovingly named Felicia, to shimmy through the dirty pipes that were clogging up the machine while harnessed to a swab dipped in a chemical cleanser. The pipes had to be spotless for the particle accelerator to work, because any imperfections would interrupt the insanely powerful beam of energy that was meant to fire through the tubes.

"Felicia is ideal for the work," said Walter Pelczarski, the lab's mechanical designer, told the Chicago Sun Times in an article archived on the Fermilab site. "The ferret is an animal filled with curiosity and seeks out holes and burrows. Its instinct is to find out what's at the other end of a burrow, or, for that matter, a tube or a pipe."

The only problem? When Felicia was first faced with the four-mile long main vacuum tube, and the lightless black oblivion that it must have appeared as, her response was (in her own ferret way): "Oh hell no."

Understandably, she refused to scamper down the hole.

Engineers are nothing if not persistent problem-solvers, though. So they designed a ferret-friendly system that allowed Felicia to start with shorter sections of tubing and eventually work her way up.

"She was taught to scamper through progressively longer tunnels until she was ready to try one of the 300-foot sections that will be joined together to make the Meson Lab's tubes," Time magazine wrote in 1971. (This article was also archived on the Fermilab site.)

Before long, the fervent ferret was merrily boring through the machine's pipes and conduits at a surprising pace. In fact, researchers soon realized they had to don Felicia with a specially-fitted ferret diaper to prevent her from spoiling any of the pipes she had just cleaned. Fermilab had become a veritable ferret playhouse.

Of course, the particle accelerator was never turned on while Felicia was scuttling through it, so she was never in any danger from the operation of the machine.

"The sections she ran through were still under construction, so I would think they wouldn't have any power running to them at that stage," Valerie Higgins, Fermilab's archivist and historian, told Jen Pinkowski in an interview for Atlas Obscura. "As far as getting stuck or suffocated goes: I think they were just relying on a ferret's instinct to explore tunnels, so I don't think she would have gone down a tunnel too small for her."

A little less than a year after Felicia first took the scrubber's reins, the particle accelerator was back up and working again. She was able to retire young and live out her remaining days in ferret bliss, fed a steady diet of snacks by Fermilab staff who treated her like one of their own.

Tragically, one night while spending the night at a Fermilab employee's residence, Felicia fell ill. She was taken to the vet immediately, but eventually succumbed to her illness on May 9, 1972.

Her contributions to Fermilab and to science will never be forgotten, though, certainly not by any of the engineers and Fermilab workers who had the pleasure of working with her.

Fermilab went on to make monumental findings, including the discovery of three of the known subatomic particles in the Standard Model.

It's fun to think that a ferret first explored the very paths those particles would later whizz along. In some way, maybe there's a hint of Felicia's spirit in each of their sparks.

That time scientists put a ferret in a giant particle accelerator...
Thankfully, no ferrets were harmed in the completion of this project.