Short answers, pulled from the story.
Stanley Cohen developed the term moral panic in a PhD thesis completed between 1967 and 1969, which became the basis for his 1972 book Folk Devils and Moral Panics. Cohen used the concept to analyze public reaction to the Mod and Rocker youth subcultures in 1960s Britain.
Cohen identified five sequential stages: a person, event, or group is perceived as a threat to societal values; the mass media amplifies the threat through simplistic rhetoric; public anxiety and concern arise from these representations; moral gatekeepers such as politicians and religious leaders respond with diagnoses and new laws; and finally the panic fades, submerges, or leaves lasting changes in law and social policy.
In their 1994 book Moral Panics: The Social Construction of Deviance, Erich Goode and Nachman Ben-Yehuda defined the five criteria as concern, hostility, consensus, disproportionality, and volatility. They argued that disproportionality is the concept's core: public concern exceeds what objective harm would warrant, and statistics are often exaggerated or fabricated.
Cohen identified mass media as the primary source of the public's knowledge about deviance and social problems. Media contribute through three processes: exaggeration and distortion of events, prediction of dire consequences if nothing is done, and symbolization, where a person or object comes to stand for an entire perceived threat.
Historic examples include the moral panic over Irish Catholic immigration in the 1840s-1850s that fueled the Know-Nothing Party, the Red Scare during 1919-1920 and again in the late 1940s-1950s, the comic book moral panic of the 1950s that led to the creation of the Comics Code, and the video game violence panic that peaked after the Columbine High School massacre in 1999.
Critics including Steve Hall (2012) argue that moral panic is a fundamental category error, because public concern is typically whipped up only to be soothed, producing complacency rather than panic. Angela McRobbie and Sarah Thornton argued in 1995 that modern media has changed so much that folk devils are now defended as well as attacked, making the classic framework outdated.