Forbidden Zone (1980). Directed by Richard Elfman

A mysterious door in the basement of the Hercules house leads to the Sixth Dimension by way of a gigantic set of intestine. When Frenchy slips through the door, King Fausto falls in love with her. The jealous Queen Doris takes Frenchy prisoner, and it is up to the Hercules family and friend Squeezit Henderson to rescue her.