Moral panic describes a situation in which societal feelings are volatile and intense about something because it seems threatening to social mores and norms. It occurs when a population begins to fear an issue or a group because they don't subscribe to some facet of life that society otherwise accepts as a norm or as being proper. The media can be influential and help the spread of moral panic by disseminating information regardless of its accuracy or if the topic is actually a real threat.
An example of a moral panic is a witch hunt such as the McCarthy anti-communist campaign in the 1950s in which a mass hysteria (a moral panic) to identify suspected Communists suspended rationality and caused many innocent people to be persecuted. Another example can be seen in the media's representation of crime. Although a person is less likely to be murdered now than in the 1950s because of the media our perception is that we are much more likely now to be a murder victim than in "the good ol' days."