Hehe Tenacious D has done the "rock duel with a demon" three times total!

1. The Tenacious D TV show - Episode 2 "The Greatest Song in the World"

2. The music video for the song "Tribute"

3. The Pick of Destiny ending scene.

I didn't have it mind but maybe subsconsciously I thought a big demonic guitar playing dragon belonged on a lonesome desert road...