Mr. Nuttel is a character from the short story "The Open Window" by Saki. He is a nervous and anxious man who visits the countryside for a break from his health issues. His visit is meant to help him recover from his nervous condition. During his stay, Mr. Nuttel meets Vera, a young girl who tells him a fabricated story about her family. This story leads to a surprising and humorous twist, showcasing Mr. Nuttel's gullibility and the cleverness of Vera. His character serves as a vehicle for the story's themes of deception and misunderstanding.