That's the question I ask in a new article at
Mysterious Universe.
You can find it at this link, and here's how it starts (the photo above shows my various books on the MIB, including overseas editions):
Back in the 1940s, the people of Mattoon, Illinois were plagued by a sinister character that became known as the Mad Gasser of Mattoon.
The name was a very apt one: the mysterious figure gassed his victims,
as a means to gain entry to their property, and to take advantage of
whatever caught his eye. His actions followed a similar wave of attacks –
in the 1930s – in Botetourt County, Virginia. But, today at least,
let’s focus on the later events. On the night of August 31, 1944, a man
named Urban Raef was overcome by a mysterious gas that provoked
sickness, weakness, and vomiting. Despite Mr. Raef’s fear that there was
a gas leak in the house, such was not the case. Rafe’s wife – to her
horror – found herself briefly paralyzed.
Also among the Gasser’s victims, was Mrs. Bert Kearney, who lived in
Mattoon, too. On September 1, 1944, and approximately an hour before the
witching-hour struck, Mrs. Kearney was hit by what was described as a
“sickening, sweet odor in the bedroom.” As was the case with Mrs. Raef,
the “gas” caused temporary paralysis in her legs. It also resulted in a
burning sensation to her lips, and a parched feeling in her mouth.