Mr. Not A Turtle is not a turtle and that's the only thing truly known about him. He prefers to not interact with any other Mr. Men or Little Misses because they may discover he is not a turtle if he says his name by accident. For example, Mr. Happy could say, "Hi, and who might you be?" and for an instant Mr. Not A Turtle could forgot to be on his guard and say, "Mr. Not A Turtle", and then the jig would be up because why else would he be named that, or at least it could cause suspicion. And only a little suspicion is all it could take
- Turtle Rock (Legend of Zelda: Link to the Past) - Also shaped like a turtle and also not a turtle.
- Batman (DC Comics) - Both are named after an animal but are not that animal and are otherwise mysterious.