Runny Babbit: A Billy Sook is the title of the last children's book by Shel Silverstein. A work in progress for the better part of 20 years, the book was published posthumously in 2005. The book is largely composed of spoonerisms in rhyming verse. Other than speaking only in spoonerisms, Runny is a normal child. He has many friends, and two loving parents, his "dummy and mad," who often remind him to "shake a tower" and other chores.