Eragon (2006)

Eragon (2006) is the worst book adaptation ever, as Stefen Fangmeier compressed Christopher Paolini's rich fantasy into a generic 104-minute Lord of the Rings knockoff. Jeremy Irons visibly regretted his involvement, and the planned franchise was killed by a 16% Rotten Tomatoes score and fan outrage. It performs even worse than The Dark Tower on this list, as that film at least earned a 16% rating whereas Eragon managed only a 15% approval on Rotten Tomatoes, and its box office of $75 million against a $100 million budget was 25% lower than the average fantasy adaptation.