Science fiction is a genre of big ideas. Unfortunately, Hollywood can't always emulate those ideas on the big screen as producers, filmmakers, executives, financiers, and all the other grubby little mitts in the fray try to meet the demands of ratings, entertainment value, run-time constrictions, screenwriting conventions, technological limitations, and the complex task of turning written language into visual language. Because of this, there are ambitious and seminal sci-fi books with bad movies hung around their necks like an iron albatross. From David Lynch's Dune to the Brad Pitt-produced World War Z, there are almost too many great sci-fi stories with terrible film adaptations to enumerate.
Many of the worst sci-fi movie adaptations were doomed from the start, as was the case with 2017's Ghost in the Shell, which cast a white woman in a traditionally Asian role. The Dark Tower adaptation from the same year remixed the events of the books so shamelessly, the film didn't even resemble Stephen King's book series.
Not all of the movie's on this list of great sci-fi stories with terrible film adaptations showed advanced warning signs of impending awfulness. Some were passion projects, such as the aforementioned Dune, which jumped from the hands of the mad auteur Alejandro Jodorowsky to the even madder David Lynch, for what could have been the greatest sci-fi movie ever made. Alas, it failed. Just like the rest of the film adaptations on this list.