The Warlock Rock

"The Warlock Rock" is a science fantasy book by American author Christopher Stasheff, published in 1990. It is the eleventh book in the Warlock of Gramarye series.

Rod Gallowglass, the Warlock in Spite of Himself, his wife Gwen, the most powerful witch of Gramarye, and their four children, Magnus, Cordelia, Geoffrey, and Gregory, go out journeying with the robot horse Fess to find the source of mysterious magical rocks which make music and capture the attention of young people. They discover not only a powerful warlock and crafter but a devious plot to destroy the heart and soul of Gramarye.

The book is filled with puns on types of rock-and-roll and famous musicians or bands. The rocks start out soft and gradually become hard. Others are covered with acid or turn into metal. Four scarab beetles (the Beatles) are observed touching the rocks and changing their music, as is a bunch of bobbed dill (Bob Dylan). Some of the stones roll down a hill and become harder as they do so ("the Rolling Stones develop [ing] into hard rock"). A monk who seeks to lead the family astray is referred to as a Judas Priest, while his good counterpart is a monk named Thelonius, and the final confrontation is with a witch seeking to perform the Black Sabbath.