The road from script to screen is often a tortured one. There will be numerous rewrites, actor changes, problems with the budget or location and a million other issues. Making any movie, even a terrible one, is punishing work. So its no wonder that movies can morph into something almost unrecognisable from their original concept. A script written as a serious drama can turn into a wacky comedy, or an action vehicle written for Tom Cruise can be retooled for Angelina Jolie instead (check out Salt for more information). Case in point: Edgar Wright had been planning Ant-Man for a decade, getting as far as pre-production and casting before creative differences with Marvel boiled up. His script was hastily rewritten and a new director brought on-board, and it seems little if any of Wrights input will remain. Likewise The Hobbit was originally planned as two movies with Guillermo del Toro helming. He worked for over a year storyboarding and designing sets and creatures, before he eventually left over delays. Peter Jackson came back, and managed to turn a small childrens book in a series of films with a combined running time of four months. This list will look at some other famous examples of movies that started life as one thing before blossoming - for better or worse - into something else. Most of them probably would have been better off sticking to the original idea.