That Is NOT a Good Idea! is a 2013 children's picture book written and illustrated by Mo Willems. First published by Balzer + Bray, it is about a plump fowl that meets a fox, and is persuaded to follow the fox to its house in the woods, all the while being observed, as if on a movie screen, by a group of young birds that regularly shout the title words. Throughout the story, the baby geese try to warn their mother that she is making mistakes.