Virgil von Vivaldi is a rocker who appears in a 2010 episode of Sesame Street. He visits the street in search of rocks so he can form a "rock band." Elmo, Zoe and Abby bring him various types of rocks, none of which are fir to be the band's lead singer. When Abby accidentally changes Chris into a gem stone, Virgil appoints him the lead singer, but Chris would rather stay human. Virgil opts to be turned into a gem instead and becomes the band's lead singer.
His character is a reference to McKean's character David St. Hubbins in the movie This is Spinal Tap. His last name, however, is based on Italian Baroque composer Antonio Vivaldi.