And the Devil Will Drag You Under

And the Devil Will Drag You Under is a comic fantasy novel by the American writer Jack L. Chalker, published in 1979.

The story starts in 2079, when an attempt to mine an asteroid ends with the asteroid redirected towards the Earth instead. As the resulting natural disasters spread across the world, two people, Mac Walters and Jill McCulloch, find themselves in Reno, Nevada, and go into a bar, where they meet a demon named Asmodeus Mogart.

The demon tells them that the Earth is only one of many thousands of universes set up by the mysterious Department of Probabilities, and that he can save it if he can gather the six pieces of a magic item. He recruits the two of them to fetch the pieces, which takes them to worlds that parody the settings of well-known fantasy novels and changes their bodies on the way. The book's title comes from a line in Sit Down, You're Rockin' the Boat, the song Frank Loesser wrote for Guys and Dolls.