The Mad Gasser of Mattoon was a tall thin man, who dressed in black and wore a tight-fitting cap. He carried a flit gun - an agricultural tool used for spraying pesticide - and crept up to people's bedroom windows at night spraying gas out of his flit gun into their rooms.
Witness testimony at the time swore to sightings of the ghastly figure and newspapers reported the story, with victims apparently becoming sick - reporting nausea and loss of limb function. The only problem with the whole thing is that The Mad Gasser of Mattoon did not exist.
Strangely, over the course of a week, 26 people reported being gassed. And yet, there was never any evidence of a prowler going around gassing people and it is generally believed to be an example of mass hysteria encouraged by lively reporting in the newspapers.
Writer of humorous novels; The Accidental Scoundrel, and Tripping the Night Fantastic.
Find them on Amazon here - https://www.amazon.co.uk/Accidental-Scoundrel-Rochdale-Manor/dp/1499628226/ref=sr_1_1?ie=UTF8&qid=1522068925&sr=8-1&keywords=the+accidental+scoundrel