Mr. Rex is a fictional character often depicted as a friendly dinosaur, typically resembling a Tyrannosaurus rex. He is commonly featured in children's books, cartoons, and educational materials, where he serves as a fun and engaging way to teach kids about dinosaurs and prehistoric life. In many stories, Mr. Rex is portrayed as curious and adventurous, exploring his surroundings and making new friends. His character often emphasizes themes of friendship, kindness, and learning, making him a beloved figure among young audiences and a popular choice for educational content related to paleontology and dinosaurs.