Here’s what you’ll learn when you read this story:

• In the 1960s, Soviet scientists “discovered” a new form of water that froze at lower temperatures and boiled at higher temperatures than normal.
• This modified water—which would eventually become known as polywater—gripped the scientific world, and experts believed it even posed an ecological threat that could impact the world’s water supply if released.
• Eventually, additional research confirmed that polywater was nothing more than water contaminated with human sweat, and the specter of polywater slowly faded into history as one of the most well-known examples of “pathological science.”

What if a lab-grown substance could escape its confines and wreak havoc on the natural world to such a degree that it extinguished life on Earth in an instant? The thought certainly crossed the mind of legendary American author Kurt Vonnegut, who published the novel Cat’s Cradle in 1963. In the novel, the U.S. government develops a deadly substance known as “ice-nine”—a strange form of water that stays frozen at room temperature and can freeze liquid water instantly on contact. Eventually, a little piece of ice-nine escapes into the world’s oceans, freezing them and effectively ending life on Earth.

Strangely, though Vonnegut couldn’t have known it at the time, Soviet scientists were at that very moment studiously exploring what they believed to be a new form of water. Similar to Cat’s Cradle, this water—developed by placing purified water into containers of different shapes—froze at far lower temperatures (around -40 degrees Fahrenheit) and boiled at much higher ones (around 400 degrees Fahrenheit) than regular water.

Discovered by Soviet scientist Nikolai Fedyakin in 1962, the creation of this modified water eventually grabbed the attention of Boris Deryagin, director of the Institute of Physical Chemistry in Moscow. Deryagin became convinced that this substance was water’s most thermodynamically stable form, and that any water that came into contact with it would similarly become this modified version. Sound familiar?

Unable to garner much excitement for his work outside the Soviet Union, Deryagin eventually gave a talk at the University of Nottingham in England, where British scientist Brian Pethica (director of the Unilever Research Laboratory in Cheshire, England) took particular interest. Giving the substance the name “anomalous water,” Pethica confirmed Deryagin’s findings and published the results in the journal Nature, hypothesizing that perhaps silicates from the glass had leached into the water, creating this strange substance as a result. This journal publication finally brought the “discovery” into the mainstream.

Magazines and newspapers wrote about this strange, potentially world-ending substance (Popular Mechanics even once published methods on how to make your own), which also gained a new name: “polywater,” a portmanteau of “polymerized” and “water.” With this news arriving at the height of the Cold War, the Pentagon soon began bankrolling efforts to “close the polywater gap” with the Soviet Union, according to The Wall Street Journal—and the fear was real. In an October 1969 edition of Nature, for example, a physicist named Frank Donahoe wrote a bone-chilling warning that would’ve felt at home in the pages of Vonnegut’s prophetic novel:

“I regard the polymer as the most dangerous material on earth,” Donahoe wrote. “Treat it as the most deadly virus until its safety is established.”

While fascination (and a little bit of panic) set in, the ruckus around polywater also inspired a cadre of disbelievers—none of whom were more ardent than Dennis Rousseau. A 29-year-old postdoctoral scientist at Bell Labs at the time, Rousseau was determined to prove that polywater wasn’t real, as he’d found high concentrations of sodium, potassium, carbon, oxygen, and chloride that seemed to point to these water samples simply being contaminated. In 1971, Science published these findings, essentially proving once and for all that polywater was pretty much water contaminated with sweat.

Today, the story of polywater is one of the most well-known examples of “pathological science”—a phenomenon where the desire to believe in a new discovery overrides the demands for well-established evidence. Other well-known examples of pathological science include N-rays (which have also been described as a mass hallucination) and cold fusion (which similarly defies many fundamental laws of nature, but gained considerable traction and interest regardless).

So, despite the fact that it didn’t amount to much in the way of major advances, polywater did reinforce a valuable lesson: in science, if something seems too good to believe, it probably is.