When movie characters possess vivid imaginations, interesting things transpire. The characters dream up imaginary friends or foes who compel them into behavior that is erratic at best and psychotic at worst. Imaginary characters can have a powerful impact on a story, causing a main character to do everything from committing murder to forming an underground fight club. These six imaginary characters play an active role in driving the actions of real people who see them.

Tyler Durden ("Fight Club"):

Creating an imaginary sparring partner ends up being a cure for insomnia for white collar drone Edward Norton. He meets Tyler Durden, played by Brad Pitt, on one of his business trips. They soon form an underground fight club and similar clubs pop up across the country. Norton soon realizes that Durden is a dissociated personality sharing his body. It's a creative way of saying he has been beating himself up the whole time.

Lloyd the Bartender ("The Shining"):

Jack Nicholson plays an alcoholic author who goes mad from writer's block and no access to alcoholic drinks while he and his family act as winter caretakers for a haunted hotel. Nicholson dreams up Lloyd the bartender, who taunts him with the promise of a drink once he murders his family. That's probably a good sign its time to enroll in a 12-step recovery program.

Wilson ("Cast Away"):

Would anyone watch Tom Hanks babbling to himself on a deserted island for two hours? Ron Howard did not want to find out, so he took the easy way out. He introduced Wilson, the volleyball that washes up with the remainder of the plane wreckage, to be a sounding board for Hanks. And it probably filled in for his other needs too.

John Shooter ("Secret Window"):

No one rivals Johnny Depp at playing crazy. “Secret Window” offers a fine example of this reality. Depp is a struggling writer who is approached by some redneck named John Shooter who claims he plagiarized a story Shooter wrote. Shooter starts killing and terrorizing people close to Depp. Then it is revealed they are one person and Depp enacts some brutal revenge on his ex-wife. Seeing it makes you not want to eat corn on the cob.

Parcher & Charles ("A Beautiful Mind"):

John Nash is a brilliant mathematician. “A Beautiful Mind” also shows he was good at filling his life with bunches of people who did not actually exist. For a time Nash worked at decoding for Parcher, the supposed head of a spy agency. He also shared an apartment with a roommate named Charles. The only problem? Neither person existed outside Nash's mind and he was forced to ignore them later to function normally enough to win a Nobel Prize. It makes you wonder how many people witnessed him talking to himself.

Frank ("Donnie Darko"):

A giant rabbit named Frank convinces a teen that the world will end in 28 days. His solution: a series of destructive acts by the teen that range from flooding his school to burning down the home of a corrupt motivational speaker. This rabbit is sort of like the rabbit from "Harvey" on steroids. Of course, everything from "Donnie Darko" is creepy and insane at the best of times.