Tenacious D
The Pick of Destiny!
(2006)

JB and KG break the pick, and the club owner gets it in his hands and transforms into the Devil. They go back outside and battle the devil; the stakes being the Devil will have to go back to hell and pay their rent, and if they lose, KG has to go back to hell and be his sex slave.

They rock!

The Devil shoots a lightning bolt at KG, it bounces off JBs guitar and hits his horn. Since the devil is not complete, he is sent back to hell.

They use the horn as the BONG OF DESTINY.

Thanks Brett!