Miss Viola Swamp is a fictional character from the children's book "Miss Nelson is Missing!" by Harry Allard. She is introduced as a strict substitute teacher who takes over the class when their regular teacher, Miss Nelson, mysteriously disappears. Miss Swamp is known for her no-nonsense attitude and her ability to instill discipline among the unruly students. The story highlights the contrast between Miss Swamp and Miss Nelson, showcasing the students' realization of how much they took their kind teacher for granted. Ultimately, Miss Swamp's tough love teaches the children valuable lessons about respect and appreciation for their teacher.