Based on

Movies like Commentary! The Musical (2008)

The cast and crew of Dr. Horrible's Sing-Along Blog (2008) perform a "most uncommon" musical commentary track for the show, acting as exaggerated versions of themselves. After reviewing the circumstances that led to the creation of Doctor Horrible, the characters sing of the contrary and cheap Joss Whedon, the aspirations of the minor actors, the egos of Nathan Fillion and Neil Patrick Harris, and everyone's favorite iPhone game.