Knight's Fork! By Rowena Cherry!
That was hilarious enough for me to look up the book, which led me to discover that it's probably titled after the chess move "forking," which led me to find this delightful gem on Wikipedia:
The type of fork is named after the type of forking piece. For example, a knight fork is a knight move that attacks two or more opponent's pieces simultaneously. Any type of piece can perform a fork[note 1]—including the king—and any type of piece can be forked. A fork is most effective when it is forcing, such as when the king is put in check.