The classic sci-fi / horror tale The Blob is about a gelatinous ball of goo that consumes everyone it can, growing bigger and hungrier as it does. It's a pretty out-there concept, so you may be surprised to find out that The Blob is based on a true story.
It might be more accurate to say that The Blob is based on a true police report. Whether or not the event actually happened has never been confirmed. In 1950 in Pennsylvania, two veteran police officers saw something fall from the sky. They described it as a "large, glittering mass drifting to earth," and when they found the landing spot in a field, they discovered a "quivering purple mound of jelly" that glittered in the light of their flashlights. It seemed to pulsate on its own, and when the cops turned off their flashlights, the mass seemed to glow on its own. For fear that no one would believe them, the cops radioed for backup. Two more police officers showed up, and one decided to try to lift it. It instantly broke apart, with tiny globules sticking to his hands. The purple goo quickly evaporated, leaving nothing behind but an "odorless residue" on the one cop's hand. The glob had evaporated completely before anyone else could arrive to see it, but a police report was filed and the newspapers ate the story up.
Seven years later, producer Jack H. Harris asked his friend, Irvine H. Millgate to come up with an idea for an original monster movie. It was the late 1950s and B-level monster movies did huge business. Harris hoped to create something a little different, so he gave Millgate a list of very specific needs: “It’s gotta be a monster movie. It’s gotta be in color instead of black and white. It can’t be a cheapy creepie, it’s gotta have some substance to it. It’s gotta have characters you can believe in. And there’s gotta be a unique monster — never been done before. And the method of killing the monster would have to be something that grandma could have cooked up on her stove.”
Millgate rememberd the tale of the cops and the purple space glob, and The Blob was born.
Source: Mysterious Universe