The mainly virtual community was thrust into the limelight just over a year ago when 25-year-old Alek Minassian drove a van into a crowd of pedestrians in Toronto, Canada, killing 10.
Before he carried out the sickening attack, Minassian made it clear what his motive was – years of being rejected by women.
Just hours before he mowed down innocent people, the student had posted on Facebook that he was murdering for the “Incel Rebellion”.
He also talked about overthrowing the “Chads and Stacys” and referenced “Supreme Gentleman Elliot Rodger”, who was another Incel mass murderer.
His final social media post shed light on a disturbing online community that is populated by angry and sexually-frustrated young men, who vent their frustrations at the world – sometimes with deadly consequences.
The term Incel comes from “involuntary celibates” – people who claim they are forced into a life of never having sex because they are rejected by potential romantic partners.
Popular social content website Reddit has numerous communities of men who frequently discuss how much they hate females, who they often refer to as “Wh*res”, “prostitutes” and “sl*ts”.
Their enemies are women, who they describe as either “Stacys or Beckys” and men they believe are more sexually successful (“Chads”).
In visual explainers posted on Reddit, so-called Stacys are essentially beautiful women who Incels claim never work, live a life of luxury that is paid for by blokes, and always get attention.
Chads are sporty and handsome men, who this twisted online community loathes for their apparent ability to attract women who they then treat badly.
Other men are “normies” – people Incels consider to be “beta males” who they claim are “wage slaves” to women.
Thousands of pages on the internet are filled with Incel rants that veer between desperate, abusive and outright threatening.
Posters have praised deadly attacks carried out by members of their communities and rejoiced at women being raped – even claiming victims enjoy being sexually assaulted.
And this burning rage sometimes spills out from the virtual world to the real one.
Elliot Rodger was 22 years old when his fury that he had “never even kissed a girl” led to him embarking on a murderous rampage.
Believing he was entitled to have sex with women, the sick killer targeted the Alpha Phi sorority, in Isla Vista, California, because its members were the “hottest” and the “kind of girls [he’d] always desired but was never able to have”.
He gunned down Katherine Cooper, 22, and Veronika Weiss, 19, members of another sorority who had the misfortune of being outside the Alpha Phi house on the day of his murderous spree in 2014.
He also knifed three men, Cheng Yuan Hong, 20, Weihan Wang, 20, and George Chen, 19, to death when he was unable to gain entry to the sorority and shot and killed 20-year-old Christopher Michaels-Martinez.
YouTube videos unearthed after the atrocity showed Bierle’s twisted rants in which he accused women of “treachery” and talked of the “virginity burden” faced by men in their adolescence.