Drummer Billy Mundi joined the Mothers of Invention during the recording of Freak Out! He performed with The Mothers in 1967 and can be heard on several of their early albums, Absolutely Free, We're Only In It For The Money, Uncle Meat and Burnt Weeny Sandwich. He quit the band after the release of We're Only In It For The Money (to be replaced by Art Tripp) to join Rhinoceros.