17. Poison Ivy (Batman & Robin)
Poison Ivy (Uma Thurman) is unquestionably one of Batman's most iconic and recognisable villains, and on paper actually seemed like a perfect fit for Joel Schumacher's more elevated, theatrical brand of Batman movies.
To her credit, Uma Thurman's commitment is never in doubt, delivering a deliciously campy performance as the seductive ecoterrorist at the center of most everybody's least-favourite Batman film.
But as a character, her Ivy is gossamer-thin at best: a chest-beating feminist who wants to save the world from "the thoughtless ravages of man," and has a whale of a time manipulating every man in her midst.
Yet there's disappointingly little meat on the character's bones and the movie never gives us much of a glimpse at Ivy's interior self, as is necessary for any great Batman villain.
Thurman tries her damnedest to rise above the weak material, but there's only so much any actor could do here.