So technically, Fred of Drop Dead Fred (not to be confused with Right Said Fred, which is an entirely different can of worms) is Lizzie's imaginary friend. But really, he's more like an imaginary albatross around her neck. Seriously, he's like a trouble-seeking missile: if there's a way for him to make her look ridiculous in public or get her carted off to a psychiatrist's office for evaluation, he's on top of it. But very deep at the bottom of his goofy, cartoonish heart, he's looking out for her best interests. He knows that she's not really happy with her condescending, philandering husband and her controlling mother running her life, and he's perfectly willing to shake things up until they turn out right. He cares for her very much, and is one of the few characters in the film who is at all concerned about what's right for her. And through the magical powers of imaginary friendship, he somehow manages to change throughout the film, being exactly the person she needs at each point in her life.