9. Parallax - Green Lantern (2011)
Hal Jordan's cinematic debut is a tepid and disorganized affair that unfortunately reeked of the hesitation studios had in adapting comic book stories to life. This can be seen in its depiction of the fear entity Parallax, who was "reimagined" as an amorphous gas cloud (a la Fox's Galactus) with a chuckle-inducing face at its centre.
Despite the entity's uninspired design, origin changes and motivations, it still proved to be a formidable foe for the Green Lantern Corps. The creature was capable of killing Green Lanterns (most notably Abin Sur), ravaging entire civililzations and a small portion of its being was capable of granting Hector Hammond psionic abilities.
So it stands to reason that the inevitable clash between Jordan and Parallax would be an awe-inspiring clash, yes? Unfortunately their climactic bout was anything but this, as Jordan ultimately prevailed by using the Sun's gravitational pull to his advantage to raze the fear entity.