Mr. Tanner was a chaperone at the Lock-In. When the kids were playing party-games, their phones would ring frequently, so he took the phones, put them in a garbage bag and locked them in a closet. When they were playing "Guess Who?" he mistook the photo of Tyson Sanders' elbow for someone's rear end. However, Tyson explained and proved that the photo was of his elbow by comparing it with the picture. Mr. Tanner looked closely at each and then realized that he made a mistake.
- Diary of a Wimpy Kid: The Ugly Truth (First and only appearance)