Demonic refers to behavior or situations possibly influenced by demons, such as unexplained evil actions or emotionally charged extreme anxiety. Demonic manifestations can occur in groups of people as well as isolated individuals, and can arise in what appears to be pure chance. Even young children can occasionally initiate demonic deeds without any non-religious explanation.
Entire nations, particularly when ethnically homogeneous, can become demonic.
Some atheists deny the existence of evil and thus deny the possibility of demonic conduct, although they may use the term for its less serious meaning to describe something similar to how evil is portrayed in movies, such as "demonic laughter."
The blockbuster movie The Exorcist famously depicted demonic conduct, supposedly based on a true story, The movie broke records for box office revenue and was upsetting to many people who saw it.