Polywater
Polywater was a hypothesized polymerized form of water that was the subject of much scientific controversy during the late 1960s. By 1969 the popular press had taken notice and sparked fears of a "polywater gap" in the USA.
Increased press attention also brought with it increased scientific attention, and as early as 1970 doubts about its authenticity were being circulated. By 1973 it was found to be illusory, being just water with any number of common organic compounds contaminating it.
Today, polywater is best known as an example of pathological science.
Background
The Soviet physicist Nikolai Fedyakin, working at a small government research lab in Kostroma, Russia, had performed measurements on the properties of water that had been condensed in, or repeatedly forced through, narrow quartz capillary tubes. Some of these experiments resulted in what was seemingly a new form of water with a higher boiling point, lower freezing point, and much higher viscosity than ordinary water, about that of a syrup.