The Mad Gasser of Mattoon (also known as the "Anesthetic Prowler," the "Phantom Anesthetist," or simply the "Mad Gasser") was the name given to the person or people believed to be responsible for a series of apparent gas attacks that occurred in Mattoon, Illinois, during the mid-1940s. More than two dozen separate cases of gassings were reported to police over the span of two weeks, in addition to many more reported sightings of the suspected assailant. The gasser's supposed victims reported smelling strange odors in their homes which were soon followed by symptoms such as paralysis of the legs, coughing, nausea and vomiting. No one died or had serious medical consequences as a result of the gas attacks.

Most contemporary descriptions of the Mad Gasser are based on the testimony of Mr. and Mrs. Bert Kearney of 1408 Marshall Avenue, the victims of the first Mattoon case to be reported by the media. They described the gasser as being a tall, thin man dressed in dark clothing and wearing a tight-fitting cap. Another report, made some weeks later, described the gasser as being a female dressed as a man. The Gasser had also been described as carrying a flit gun, an agricultural tool for spraying pesticide, which he purportedly used to expel the gas.

Police remained skeptical of the accounts throughout the entire incident. Many reported gassings had simple explanations, such as spilled nail polish or odors emanating from animals or local factories. Victims made quick recoveries from their symptoms and suffered no long-term effects. Nevertheless, local newspapers ran alarmist articles about the reported attacks and treated the accounts as fact.

The attacks are widely considered to be a case of mass hysteria. However, others maintain that the Mad Gasser actually existed, or that the perceived attacks have another explanation. There are three primary theories about the Mattoon Mad Gasser incident: mass hysteria, industrial pollution, or an actual physical assailant. The events have also been written about by authors on the paranormal.

A list of gas attacks are listed below:
{| class="fandom-table"
!Date
!Victim(s)
!Location
!Notes
|-
|Aug 31, 1944
|Mr. and Mrs. Urban Raef
| Grant Avenue
|
|-
|Sept 1
|Unnamed
|
|Name not reported in the media
|-
|Sept 1
|Mrs. Charles Rider
|Prairie Avenue
|
|-
|Sept 1
| Aline Kearney
|Marshall Avenue
| First case reported in the media; most Gasser descriptions derive from this case
|-
|Sept 5
|Mrs. Beulah Cordes
| North 21st Street
|Became ill after smelling cloth found on porch
|-
|Sept 5
|Mrs. Leonard Burrell
| North 13th Street
|
|-
|Sept 6
|Mrs. Laura Junken
|Richmond Avenue
|
|-
|Sept 6
|Ardell Spangle
| North 15th Street
|
|-
|Sept 6
|Mr. Fred Goble
|
|Saw prowler believed to be Gasser
|-
|Sept 6
|Mrs. Glenda Hendershott
| South 14th Street
|
|-
|Sept 6
|Mr. Daniel Spohn
| North 19th street
|
|-
|Sept 6
|Mrs. Cordie Taylor
|Charleston Avenue
|
|-
|Sept 6
|Miss Frances Smith
Miss Maxine Smith
|Moultrie Ave
|
|-
|Sept 7
|As Above
|As Above
|Saw blue vapor and heard a motorized buzzing sound believed to be from ''gassing machinery''
|-
|Sept 8
|Mr C.W. Driskell
|DeWitt Avenue
|
|-
|Sept 9
|Mrs. Genevieve Haskell
Grayson Wayne Haskell
Mrs. Russell Bailey
Miss Katherine Tuzzo
|Westwood
|
|-
|Sept 9
|Mrs. Lucy Stephens
| North 32nd Street
|
|-
|Sept 10
|Unnamed
|Champaign Avenue
|Name not reported in the media
|-
|Sept 10
|Unnamed
|2112 Moultrie Avenue
|Name not reported in the media
|-
|Sept 10
|Miss Frances Smith
Miss Maxine Smith
|Moultrie Ave
| Third reported attack
|-
|Sept 13
|Bertha Burch
|
|Described gasser as being a woman dressed as a man; woman's footprints found at scene
|}

*[https://en.wikipedia.org/wiki/Mad_Gasser_of_Mattoon#Other_suggestions Wikipedia]
*[https://monsterinmypocket.fandom.com/wiki/Mad_Gasser_of_Mattoon Monster in My Pocket Wiki]
*[https://comicvine.gamespot.com/mad-gasser-of-mattoon/4050-125051/ ComicVine]
*[https://obscurban-legend.fandom.com/wiki/Mad_Gasser_of_Mattoon ObscUrban Legend Wikia]
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