In 1958, she played in several B movies, including "Wolf Dog" as well as taking the lead role in "Attack of the 50 Foot Woman", where she plays the part of an abused socialite who grows to giant size because of an alien encounter. In this film, she starred with Yvette Vickers and William Hudson, and it is probably her best-known role. With its science fiction storyline and low budget, the film attained popularity with some movie fans, and in the subsequent years has attracted a cult film following based primarily on Hayes spending almost all the time she is enlarged calling for "Harry!" as she angrily searches for her philandering husband. The film did not lead to better roles, though she remained constantly employed and found work as a model. During 1963 and 1964, she played a continuing role in the "General Hospital" but by this time her movie career was virtually over.