Mesogog is a fictional character from the television series Power Rangers Dino Thunder. He serves as the main antagonist and is known for his desire to create a world dominated by dinosaurs. Mesogog is a powerful and ancient being who can transform into a dinosaur-like form, showcasing his connection to prehistoric creatures. In the series, Mesogog is portrayed as a former human named Anton Mercer, who was transformed by a failed experiment. He commands an army of evil creatures and seeks to eliminate humanity to establish his vision of a dinosaur-ruled world. His character adds depth to the show's themes of good versus evil.