theomania (thee-o-MAY-nee-uh, -MAIN-yuh) noun
The belief that one is God or specially chosen by God on a mission.
[From Greek theos (god) + -mania (excessive enthusiasm or craze).]
Jake: First you traded the Cadillac in for a microphone. Then you lied to me about the band. And now you're gonna put me right back in the joint!
Elwood: They're not gonna catch us. We're on a mission from God.