Dreamcatcher (2003)

What fills some 600 Stephen King-size pages is too much and too messy in this unintelligible adaptation of King's 2001 novel about government conspiracy, boyhood friendship, and -- especially -- an alien worm that emerges from the anus of its human carrier in a sploosh of funny-gory goo. Morgan Freeman plays a bonkers, alien-chasing colonel; Donny Wahlberg plays a guy brain-damaged to look at, supernaturally gifted to know. The extraterrestrial, opportunistic tush parasite is played by a whole lot of F/X specialists wriggling as a team.