In David Fincher's adaptation of Chuck Palahniuk's book, the Narrator, a former office drone, discovers that his buddy, Tyler Durden (Brad Pitt), an anti-materialist who freed him from his complacent cubicle life and is plotting to blow up credit card company buildings and destroy debt records that shackle consumers, is actually his own dissociated personality. 

To reclaim his body from Tyler, who holds him at gunpoint when he attempts to stop the bombings, the Narrator eats the gun, which was in his own hand the whole time, and blasts a non-fatal hole through his cheek. Tyler's shit is blown loose and the Narrator lives on, fully in cognizant control of his actions, to watch as the explosives detonate. Schizophrenic win-win.