Marilyn Munster is a fictional character in the CBS sitcom The Munsters, originally played by Beverley Owen and later by Pat Priest. In the original series, she is the daughter of Lily Munster's sister, with Herman alluding to her "plain" looks coming from Lily's side of the family. She was played by Hilary Van Dyke in the 1988 series The Munsters Today.
Played first by Beverley Owen and then by Pat Priest, Marilyn lives with the Munsters throughout the series run. It never is made clear why Marilyn lives with the Munsters rather than with her parents, who are said to still be in Transylvania. Although she is Lily's niece, she always is referred to as Marilyn Munster. Marilyn states in the first aired episode that she has lived with the Munsters since she was a baby.
Marilyn is a fetching young woman and the only family member who is not ghoulish in appearance; by the Munsters' aesthetic standards, she is distressingly unattractive. The family views Marilyn's appearance as an affliction, but still treat her with kindness and love. Marilyn is all too aware of her "homeliness" and laments that she keeps scaring potential boyfriends, having no clue that the young men are frightened away by her monstrous family.
She attends Westbury College in Mockingbird Heights. She is devoted to her family, and the surest way for a suitor to alienate Marilyn (rather than vice versa) is to disparage them. She considers her Uncle Herman and Grandpa the "two [finest] men [who ever] walked this earth."
Despite being a “normal” beauty by society standards, the Munsters’ strange subculture of vampires, werewolves, and mad scientists, et al., have made her a ghoul at heart (she regularly assists Lily in cooking oddities and festooning the house with cobwebs). Like the rest of her family, she believes that the Munster lifestyle is normal, and dissenters are out of step. In one episode, Herman temporarily was transformed into a normal, clean-cut man. The family, including Marilyn, was appalled and physically repulsed by the tragic event.
Despite standing out among the cast more than any other character, Marilyn was the least developed character in the series. She usually served as an ear for Lily's expeditions or a subject for Grandpa's foiled potions.