Ivy's Poison Kiss
This film actually caused a misunderstanding about Poison Ivy's ability to poison anybody she kissed on the lips. In this story, she unnaturally produces venom from her lips, due to the mutations that came from her transformation in the lab in South America.
Turns out, in the comics, and some of the cartoons, that isn't the case at all. I re-watched the Animated Series, and on there, Poison Ivy would actually put special lipstick on before poisoning her victims. She made it herself, and probably had given herself an antidote beforehand. The original Poison Ivy wasn't nearly as fantastical as the one in this movie. She apparently had to inject herself with anti-toxins all the time because of the nature of her hideout (the cartoon indicated she deliberately had it hidden in a garbage dump full of toxic waste), and her work with poisonous (sometimes carnivorous) plants.
Trouble is, there are several ways to interpret her as a supervillain, and this movie went down the path of making it seem like she had become a human/plant mutant.