As in most stories, "The Monkey's Paw," by W.W. Jacobs has both dynamic and static characters who help move the plot forward. Dynamic characters go through some kind of inner change, often one that affects them deeply, whereas static characters remain virtually the same as they were when first introduced. Mr. and Mrs. White both change greatly in "The Monkey's Paw." They go from being fairly happy with their lives to a desperate sadness when they lose their son.
Their son, Herbert, on the other hand, is a static character. He does not change, even though his character is very important to the plot. Sergeant Major Morris is also a flat character. He is the one who sets the story in motion with the monkey's paw, but there is no change in his character over the short time he is present.