Regan MacNeil is a character from the 1971's horror novel The Exorcist, but made extremely popular by the 1973's film adaptation of the novel. Regan is a 12-year-old girl who gets possessed by the demon, Pazuzu (also seen in some screamers), making her unable to control her own actions.
Regan MacNeil's role was played by Linda Blair, an American actress.
In Popular culture
In The Episode "Halloween". Dilan puts his mask that have the screamer picture but with the full body